Why Does My Washing Machine Smell?
A pungent, musty, or even sour smell emanating from your washing machine is a familiar problem for many households. This unpleasant odour is typically not a sign of a serious fault but rather a build-up of residue, mould, and bacteria within the appliance. Understanding the root causes is the first step towards effectively eliminating the smell and restoring freshness to your laundry.
Several factors contribute to that tell-tale aroma. Modern washing machines, especially front-loaders, often use lower wash temperatures and shorter cycles, which are energy efficient but can leave behind soap scum, fabric softener residue, and dirt. These organic materials create a damp, dark environment perfect for mould and mildew to thrive. Furthermore, residual moisture trapped in the drum, door seal, and detergent drawer can harbour unpleasant bacteria. Over time, this combination of dampness and organic matter decomposes, producing the distinctive smell.
Key culprits include:
- Detergent and Softener Residue: Using too much detergent or fabric softener can lead to a sticky film inside the drum and pipes, which bacteria love.
- Low-Temperature Washes: Frequent use of cold water cycles, while economical, may not be hot enough to break down and wash away bacteria and detergent build-up effectively.
- Trapped Moisture: Leaving the washing machine door or detergent drawer closed immediately after a cycle prevents proper ventilation, allowing moisture to linger and encourage mould growth.
- Washing Dirty Items: Heavily soiled items, like gym clothes or work uniforms, can introduce more bacteria and grime that may not be fully eliminated by standard washes.
- Blocked Filter or Drain: A clogged washing machine filter or drain can trap water and debris, creating a stagnant, smelly environment.
When you notice a persistent smell, it's crucial to address it promptly. Ignoring it can lead to the odour transferring to your clothes, negating the purpose of doing laundry.
The primary cause of a smelly washing machine is invariably a build-up of residual detergent, fabric softener, and organic matter, which breeds mould and bacteria in damp conditions.
Identifying the Source
Before embarking on a cleaning regimen, it helps to pinpoint where the smell is strongest. Open the door and take a sniff. Does the smell seem strongest inside the drum itself? Is it emanating from the rubber door seal, often a dark, crevice-filled area? Or is the odour concentrated around the detergent drawer or the washing machine filter?
A visual inspection is also informative. Look for any visible mould growth, particularly around the door seal, inside the detergent dispenser, and on the inside of the drum. Check the washing machine filter – usually located at the bottom front of the machine behind a small panel – for any trapped lint, hair, or debris, which can become waterlogged and exceptionally foul-smelling. The rubber seal on front-loading machines is notorious for collecting hair, lint, and residual water, making it a prime spot for mould and mildew.
Sometimes, the smell can be a deeper issue within the pump or drainage system, but for most users, the problem is accessible and rectifiable through regular, thorough cleaning. These common areas are the first places to investigate when troubleshooting that unpleasant odour.
Step-by-Step Diagnostic Procedure
To diagnose the smell systematically, follow these checks:
- Drum Check: After a wash, smell the inside of the empty drum. Is it musty or stale?
- Door Seal Inspection: Pull back the rubber gasket of the door (especially on front-loaders) and look for discolouration, residue, or visible mould. Smell this area specifically.
- Detergent Drawer Assessment: Remove the detergent drawer if possible. Check for dried-on residue, mould, or a pungent odour emanating from the compartments.
- Filter Examination: Locate and carefully remove the washing machine filter. Inspect it for trapped debris and assess its smell. Be prepared for water to drain out.
- Drain Hose Check: Ensure the drain hose isn't kinked or blocked, which could cause water to back up and stagnate.
By performing these checks, you can often identify the most problematic areas and tailor your cleaning approach accordingly. If the smell persists after addressing these, it might indicate a deeper internal issue, but for the vast majority of cases, these common areas are the source.
Materials Needed for a Deep Clean
Before you begin tackling that persistent smell, gathering the right supplies will make the process more efficient. You don't need specialised, expensive products for most cleaning tasks; common household items often suffice. Ensure you have protective gear, especially if you're sensitive to cleaning chemicals or mould spores.
Here's a list of items you'll likely need:
- White Vinegar: A natural disinfectant and deodoriser that helps break down soap scum and mineral deposits. About 250-500 ml (1-2 cups) is usually sufficient for a single clean.
- Baking Soda: An excellent deodoriser and mild abrasive. You'll need about 50-100g (1/4-1/2 cup).
- Microfibre Cloths or Sponges: For wiping down surfaces and scrubbing. Have a few dedicated cloths to avoid cross-contamination.
- An Old Toothbrush or Small Scrub Brush: Ideal for getting into tight crevices, such as the door seal and detergent drawer compartments.
- Gloves: To protect your hands from cleaning solutions and any unpleasant residue.
- Bucket or Bowl: To hold cleaning solutions or collect water and debris.
- Optional: Washing Machine Cleaner Product: While vinegar and baking soda are effective, commercial washing machine cleaner products (like Calgon, Dr. Beckmann, or Dettol washing machine cleaner) are formulated for this purpose and can be used as an alternative or supplement. Check the product packaging for usage instructions.
- Optional: Bleach (Diluted): For stubborn mould, a very dilute bleach solution can be effective, but use with extreme caution and never mix with vinegar. Ensure good ventilation.
- Old Towels or Paper Towels: To dry components and mop up spills.
Having these items on hand ensures you're prepared for a thorough clean, addressing both surface grime and deeper build-up. For instance, a good washing machine cleaner can be a powerful ally, but understanding how to use it correctly, including recommended dosages and cycle settings, is key.
Having white vinegar, baking soda, and suitable cleaning cloths ready ensures you are well-equipped to tackle common washing machine odours effectively.
Choosing Your Cleaning Agents
The choice between natural remedies and commercial cleaning products often comes down to personal preference and the severity of the smell. White vinegar is a time-tested, affordable, and eco-friendly option. Its acidity helps to dissolve mineral deposits and soap scum while also acting as a mild disinfectant. Baking soda, being alkaline, neutralises acidic odours and acts as a gentle scouring agent, ideal for scrubbing away residue. Together, they can form a powerful cleaning duo.
Commercial washing machine cleaners, such as Calgon, Dr. Beckmann washing machine cleaner, or Dettol washing machine cleaner, are specifically formulated to combat limescale, detergent build-up, and bacteria. They often contain enzymes and surfactants designed to break down grime more aggressively than vinegar alone. If you opt for a commercial product, always follow the manufacturer's instructions precisely, as they may require a specific wash cycle or dosage. When comparing brands, consider looking for those that target limescale removal as well as general cleaning, as hard water can exacerbate build-up.
Bleach is a potent disinfectant but should be used sparingly and with extreme care. It is highly effective against mould and mildew but can damage rubber seals over time if used too frequently or in high concentrations. Critically, never mix bleach with vinegar or any acidic cleaner, as this can produce toxic chlorine gas. If using bleach, ensure the washing machine compartment is well-ventilated and rinse thoroughly.
The Method: How to Clean Your Washing Machine
Now that you have your supplies, it's time to get your washing machine smelling fresh again. This method involves cleaning all accessible parts thoroughly, followed by a hot cycle to flush out residual grime.
Cleaning Accessible Components
Start by addressing the areas you can easily reach and clean manually:
- Detergent Drawer: Remove the detergent drawer completely if possible. Soak it in warm, soapy water for about 30 minutes. Use an old toothbrush or a small scrub brush to remove any hardened residue, mould, or slime from all compartments and runners. Rinse thoroughly and dry before replacing.
- Door Seal (Front-Loaders): Gently pull back the rubber door seal. You'll likely find trapped lint, hair, and potentially mould. Spray a mild solution of water and vinegar (or a diluted bleach solution, if necessary, with caution) onto a microfibre cloth and carefully wipe down the entire seal, paying close attention to the folds and crevices. Use the toothbrush for stubborn spots. Wipe clean with a damp cloth and then dry thoroughly. Leave the door ajar after cleaning to allow it to air out.
- Glass Door: Wipe down the interior and exterior of the glass door with a damp cloth to remove any soap residue or streaks.
- Washing Machine Filter: Place old towels or a shallow tray underneath the filter access panel to catch any water. Slowly unscrew the washing machine filter. Remove any trapped debris, lint, or foreign objects. Rinse the filter under running water, scrubbing gently if needed with a brush. Dry the filter and the housing before screwing it back in securely.
These manual steps are vital for removing the visible build-up that contributes significantly to the smell. Don't underestimate the importance of these fiddly bits!
Pro Tip: For persistent mould on the door seal, try applying a paste of baking soda and water, letting it sit for 15-30 minutes before wiping away. This offers a gentler yet effective way to lift staining and odour.
Running a Hot Cleaning Cycle
Once the accessible components are clean, it's time to tackle the internal workings of the machine.
- With Vinegar: Pour approximately 250-500 ml (1-2 cups) of white vinegar directly into the detergent drawer (or into the drum if your machine has a specific cleaning cycle that advises this).
- With Baking Soda: Add about 50-100g (1/4-1/2 cup) of baking soda directly into the empty drum.
- With Commercial Cleaner: If using a dedicated washing machine cleaner (like Calgon, Dr. Beckmann washing machine cleaner, or Dettol washing machine cleaner), follow the specific instructions on the product packaging for dosage and placement (usually in the detergent drawer or directly in the drum).
- Select Cycle: Run the washing machine on its hottest possible cycle (e.g., 90°C or a 'hot wash' or 'tub clean' cycle if available). Let the cycle complete fully.
This hot wash helps to break down any remaining soap scum, detergent residue, and kill lingering bacteria and mould spores. The combination of vinegar or a cleaner with the high heat is very effective. If you used both vinegar and baking soda, you might notice some fizzing; this is normal and part of the cleaning action. After the cycle finishes, wipe down the drum interior with a clean, dry cloth to remove any loosened residue.
The crucial step is running a high-temperature wash cycle after cleaning components to flush out internal build-up.
Checking the Drain Hose
Sometimes, the smell can be exacerbated by a blocked or improperly draining hose. After the cleaning cycle, check the drain hose at the back of the machine. Ensure it's not kinked, which can prevent water from draining correctly, leaving stagnant water that breeds smells. If the hose appears to be draining slowly, or if you suspect a blockage further down, you may need to disconnect it (with a bucket ready for residual water) and inspect it for obstructions. A blocked drain hose can contribute significantly to a persistent, foul odour.
Tips for Preventing Future Smells
Getting rid of the smell is only half the battle; the real goal is to prevent it from returning. Regular maintenance and a few simple habit changes can keep your washing machine smelling fresh and functioning optimally for years to come.
Preventing that musty odour involves creating an environment where mould and bacteria cannot thrive. This means minimising moisture, ensuring good ventilation, and preventing excessive residue build-up. Implementing these practices after your initial deep clean will make a significant difference in maintaining a neutral-smelling appliance.
Here are some key preventative measures:
- Leave the Door Ajar: After every wash, leave the washing machine door open for a few hours, or at least until the drum is dry. This allows air to circulate and prevents moisture from getting trapped, which is a primary cause of mould growth. For front-loaders, ensure the rubber seal is also wiped dry and left open to the air.
- Remove Laundry Promptly: Don't leave damp clothes sitting in the washing machine for extended periods. This creates a breeding ground for bacteria and can transfer odours to your clean laundry. Remove clothes as soon as the cycle finishes.
- Use the Right Amount of Detergent: Overdosing on detergent or fabric softener is a common mistake. Modern machines and detergents are highly efficient, so using less than you think you need is often sufficient. Excess product leads to residue build-up, which feeds mould and bacteria.
- Regular Hot Washes: Supplement your regular washes with a hot water cycle (60°C or higher) at least once a month. This helps to kill bacteria and dissolve detergent build-up more effectively than lower temperatures. If you frequently wash at low temperatures, this is especially important.
- Clean the Detergent Drawer Regularly: Wipe down the detergent drawer weekly to remove any residual product. If it's removable, give it a proper clean every month or two.
- Clean the Filter Monthly: Make it a habit to check and clean your washing machine filter at least once a month. This simple task prevents blockages and removes trapped debris that can decompose and smell.
- Wipe Down the Door Seal: Quickly wipe the rubber door seal and the inside of the door glass with a dry cloth after each wash to remove excess moisture and lint.
Consistent application of these simple habits will go a long way in keeping your washing machine free from odours and your laundry smelling clean and fresh.
The most effective way to prevent washing machine smells is by ensuring the appliance dries out thoroughly between uses and using appropriate amounts of detergent.
Pro Tip: If you have hard water, consider using a limescale remover regularly, perhaps using a product like Calgon or a specific washing machine cleaner designed for hard water. Limescale can trap detergent residue and create a more porous surface for bacteria to adhere to.
Washing Machine Filter Maintenance
The washing machine filter, often overlooked, plays a critical role in machine health and odour prevention. Located at the bottom of most machines, it catches lint, hair, coins, and other small items that could otherwise clog the pump or drainage system. A clogged filter can trap water, leading to stagnation and a foul smell.
To clean the filter:
- Locate: Find the filter, usually behind a small flap or panel at the front bottom of the machine.
- Prepare for Drainage: Place old towels or a shallow tray beneath the filter to catch water that will inevitably drain out when you open it.
- Unscrew Carefully: Slowly unscrew the filter. Water will begin to drain. Let it empty into your tray or bucket.
- Clean Debris: Once the water has drained, remove the filter completely. Pull out any lint, hair, coins, or other foreign objects.
- Rinse and Scrub: Rinse the filter under running water. Use an old toothbrush to scrub away any stubborn grime or slime.
- Check Housing: Inspect the filter housing for any remaining debris and wipe it clean.
- Reassemble: Screw the clean filter back into place securely. Ensure it's tight to prevent leaks.
Performing this task monthly is a highly effective method for preventing smells and ensuring your machine drains properly. A clean filter contributes to better water circulation and less stagnant water inside the machine.
Optimising Detergent Use
Using the correct amount of detergent is vital. Modern high-efficiency (HE) washing machines require significantly less detergent than older models. Overusing detergent leads to excessive suds, which can leave a residue on clothes and inside the washing machine. This residue is a prime food source for mould and bacteria. Fabric softeners can also contribute to build-up, particularly in the door seal and dispenser. If you use fabric softener, consider reducing the amount or using it only for specific items.
Always refer to your detergent's packaging and your washing machine's manual for recommended dosages based on load size and water hardness.
If you have soft water, you may need even less detergent. For hard water, while you might need a little more to counteract mineral build-up, it's still essential to avoid overdosing. Using a washing machine cleaner that specifically targets limescale can help manage hard water issues without excessive detergent use. Periodically, try running a load with no detergent at all, just hot water, to help flush out accumulated residue.
Troubleshooting Persistent Odours
If you've followed the cleaning steps and your washing machine still smells, it's time to investigate further. Persistent odours can sometimes indicate issues that require a bit more attention or a different approach to cleaning. Don't get discouraged; most washing machine smells are treatable with a little persistence.
When the standard vinegar and baking soda treatment doesn't yield the desired results, consider the possibility that the build-up is more stubborn or located in areas not easily reached by a simple cleaning cycle. This might be due to prolonged neglect, extremely hard water, or washing particularly soiled items regularly without adequate pre-treatment or hotter cycles.
Here are some troubleshooting steps for lingering smells:
- Repeat the Deep Clean: Sometimes, one clean isn't enough. If the smell is particularly deep-seated, repeat the hot wash cycle with vinegar and baking soda (or a strong commercial washing machine cleaner) a second or even third time. Ensure you clean the accessible parts thoroughly before each cycle.
- Focus on the Door Seal: For front-loaders, the door seal can harbour mould deep within its folds. Carefully inspect the entire circumference, using a damp cloth or old toothbrush to dislodge any hidden mould. A diluted bleach solution (1 part bleach to 10 parts water) can be used for stubborn mould, but rinse very thoroughly afterwards and ensure good ventilation.
- Check the Detergent Dispenser Thoroughly: Some dispensers have removable parts or hidden compartments where mould can grow. If yours is removable, soak it for longer, and use a pipe cleaner or small brush to get into all the nooks and crannies.
- Inspect the Drum Itself: Look for any signs of damage or persistent residue stuck to the inside of the drum walls or under the agitator (in top-loaders).
- Consider the Drain Pump and Hose: If the smell persists and you've cleaned everything else, the issue might be in the drain pump or the internal drain hose. These are harder to access and might require professional attention if they are blocked or have accumulated significant sludge. A common mistake is not realising how much residue can accumulate here.
- Ventilation: Ensure the laundry area itself is well-ventilated. A damp, poorly ventilated laundry room can contribute to a musty smell that seems to come from the machine.
If the smell is intensely foul and doesn't improve after multiple deep cleans, inspect the washing machine filter and the rubber door seal with extreme care.
Dealing with Stubborn Mould
Stubborn mould requires a more robust approach. While vinegar is good, for tough mould spots, especially on the rubber door seal of a front-loader, a diluted bleach solution is often the most effective. Mix 1 part household bleach with 10 parts water. Apply this solution to a cloth and carefully wipe the affected areas. Allow it to sit for a few minutes, then scrub gently with a toothbrush if needed. Crucially, rinse the area thoroughly with clean water afterwards, and then wipe dry. Ensure the room is well-ventilated when using bleach, and never mix it with vinegar or ammonia-based cleaners.
After treating visible mould, run a high-temperature cleaning cycle with a washing machine cleaner designed to kill mould and mildew, or use plain hot water to ensure all traces are removed from the machine's internal parts.
When to Call a Professional
If you have tried all the above methods, including multiple deep cleans with appropriate products, and the smell stubbornly persists, it might be time to consult a professional appliance repair technician. There could be an internal blockage in the drain pump, a problem with the heating element, or a build-up of residue in parts of the machine that are not accessible for manual cleaning. A technician can diagnose and fix these more complex issues, potentially saving you from needing to replace the entire appliance prematurely. They have the tools and expertise to safely dismantle parts and clear blockages that are beyond the scope of typical home maintenance.
Understanding Different Washing Machine Types
While the core principles of keeping a washing machine smelling fresh apply across the board, there are nuances between different types of machines that can affect how and where smells develop, and how you should approach cleaning them.
The two main categories are top-loading and front-loading washing machines. Each has its own unique design features that can lead to specific odour issues and require slightly different cleaning techniques. Understanding these differences helps you target your cleaning efforts more effectively.
Front-Loading Washing Machines
Front-loaders are known for their energy and water efficiency, often using less water and performing more rotations to clean clothes. However, this design also makes them more prone to smells. The main reasons are:
- Door Seal: The rubber gasket around the door is a prime location for mould and mildew to grow. It traps moisture, lint, and detergent residue. This is arguably the most common source of smell in front-loaders.
- Lower Water Levels: They tend to use less water, which means detergent and dirt may not be fully rinsed away, leading to build-up.
- Trapped Moisture: If the door is kept shut, water can stagnate in the drum and seal.
For front-loaders, rigorous cleaning of the door seal and ensuring the door is left ajar are paramount. Using a washing machine cleaner designed for these machines can be particularly beneficial to combat the residue build-up.
Top-Loading Washing Machines
Top-loaders come in two main varieties: traditional agitator models and high-efficiency (HE) impeller models. While generally less prone to the seal-related mould issues of front-loaders, they can still develop smells.
- Agitator Models: These use a central post (agitator) to move clothes. Residue can build up around the base of the agitator and under the lid.
- HE Impeller Models: These use a low-profile cone or disc at the bottom to move clothes. They use less water, similar to front-loaders, and can also suffer from detergent residue build-up in the drum and around the impeller.
- Lid Propping: Like front-loaders, leaving the lid open after use is crucial for ventilation.
For top-loaders, the cleaning cycle is key, and manual cleaning should focus on the lid, the top rim of the drum, and around the agitator or impeller. Ensure the water can circulate freely to wash away cleaning agents.
Regardless of type, the fundamental principles of hot washes, regular filter cleaning, and proper ventilation are key to preventing smells.
Washer-Dryer Combos
These all-in-one units present unique challenges. Because they are enclosed and designed to perform both functions, moisture can be retained for longer periods. If the drying cycle isn't entirely effective or if the machine isn't used correctly, dampness can persist. The internal mechanisms are often more complex, and accessing certain areas for cleaning might be more difficult. It is especially important to leave the door ajar and run cleaning cycles regularly. Some washer-dryer combos also have specific cleaning modes designed to purge residual moisture and clean the internal drum.
For all types of machines, remember that the washing machine filter is a common point of failure and smell, so regular cleaning is universally important.
Preventative Maintenance Schedule
Establishing a regular maintenance schedule is the most effective strategy to prevent your washing machine from developing an unpleasant odour in the first place. Think of it as a routine health check for your appliance. By dedicating a small amount of time regularly, you can avoid the more intensive deep cleans and ensure your laundry always smells fresh.
A structured approach ensures that all critical components are addressed at appropriate intervals. This prevents the gradual build-up of residue, mould, and bacteria that leads to those stubborn smells. Consistency is key; making these tasks part of your household routine will pay dividends.
Weekly Tasks
- Wipe Down Door/Lid and Seal: After each wash, wipe the door (or lid) and the rubber seal (on front-loaders) with a dry cloth. This removes residual moisture and lint.
- Leave Door/Lid Ajar: Ensure the door or lid is left open between uses to allow air circulation and drying.
- Wipe Dispenser: Quickly wipe down the detergent dispenser to remove any immediate residue.
Monthly Tasks
- Clean the Washing Machine Filter: Remove, clean, and replace the washing machine filter. This is crucial for preventing blockages and removing trapped debris.
- Clean the Detergent Drawer: Remove the detergent drawer (if possible) and give it a more thorough clean to remove any build-up or mould.
- Wipe Drum Interior: Give the inside of the drum a quick wipe with a damp cloth to remove any visible residue.
Quarterly (Every 3 Months) Tasks
- Deep Clean Cycle: Run a hot wash cycle (minimum 60°C, ideally 90°C or a 'tub clean' cycle) using white vinegar and baking soda, or a dedicated washing machine cleaner product. This flushes out internal components and kills bacteria.
- Scrub Door Seal (Front-Loaders): Give the rubber door seal a more thorough scrub, especially into the folds, to remove any emerging mould or grime.
Bi-Annual (Every 6 Months) Tasks
- Inspect Drain Hose: Check the drain hose for kinks or blockages. Ensure it's securely connected.
- Run a High-Heat Cycle (No Detergent): If you suspect significant detergent build-up, run an extra hot wash cycle with no detergent to help flush out residues.
Adhering to a regular cleaning schedule is the most effective strategy for preventing unpleasant washing machine smells long-term.
Pro Tip: If you live in an area with very hard water, consider using a limescale-inhibiting product (like Calgon) in every wash, or use a specific washing machine cleaner designed for limescale removal quarterly, in addition to your standard cleaning cycle.
The Role of High-Temperature Washes
High-temperature washes are essential for hygiene. While low-temperature cycles are energy-efficient and suitable for most everyday laundry, they don't always reach temperatures high enough to kill bacteria and mould spores effectively. Regularly running your machine on a hot cycle (60°C or above) helps to sterilise the drum, kill microbes, and dissolve detergent and soap scum that accumulate over time. This is particularly important if you frequently wash items like towels, bedding, or sportswear, which can harbour more bacteria. Incorporating at least one hot wash per month into your routine is a simple yet highly effective preventative measure against both smells and potential hygiene issues.
Frequently Asked Questions About Washing Machine Smells
Many users encounter washing machine odours and have similar questions about their causes and solutions. Here are answers to some common queries to help you maintain a fresh-smelling appliance.
Understanding the specifics of washing machine maintenance can demystify common household issues. Addressing smells promptly and consistently is key to appliance longevity and the cleanliness of your laundry.
How often should I clean my washing machine to prevent smells?
For best results, aim for a light clean weekly (wiping seals and leaving the door ajar), a more thorough clean of components like the filter and drawer monthly, and a deep cleaning hot cycle quarterly. This preventative schedule significantly reduces the likelihood of odours developing.
Can I use bleach to clean my washing machine?
Yes, a diluted bleach solution (1 part bleach to 10 parts water) can be used cautiously, especially for stubborn mould on door seals. However, never mix bleach with vinegar or ammonia, and ensure good ventilation. Rinse thoroughly after use. Frequent high-concentration bleach use can degrade rubber parts over time.
Why do my clothes smell after washing?
If your clothes smell after washing, the issue likely lies with the washing machine itself. The smell originates from mould, bacteria, or detergent residue within the machine that hasn't been adequately removed. Ensure you are running hot washes regularly and cleaning the appliance thoroughly.
What is the best washing machine cleaner?
Effective options include natural remedies like white vinegar and baking soda, or specific commercial products such as Calgon, Dr. Beckmann washing machine cleaner, or Dettol washing machine cleaner. The 'best' often depends on the specific issue (e.g., limescale vs. general grime) and personal preference. Always follow product instructions.
Should I leave the washing machine door open after use?
Absolutely. Leaving the door (or lid) of your washing machine open between washes is one of the most critical steps for preventing smells. It allows moisture to evaporate, which is vital for stopping mould and bacteria from growing in the damp environment.
