How to Remove Mould from Mattress Easily in 2025 [Ultimate Guide]

NOV 25, 2025

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Finding mould on your mattress is something nobody wants to wake up to—but it’s more common than you think. Whether you live in a humid area, sleep hot, or rarely air out your bedroom, mould can quietly grow inside the foam layers or along the fabric seams of your bed. The problem isn’t just unpleasant; it can trigger allergies, affect your breathing, and shorten the lifespan of your mattress.

In this guide, we’ll walk you through why mould happens, how to spot the early signs, and—most importantly—how to get rid of mould on mattress safely with simple household methods. Let’s fix the problem now and stop it from returning.

Table of Contents

1. The Dangers of Mould 2. How Mould Forms on a Mattress 3. 5 Signs Your Mattress Has Mould 4. How to Remove Mould in 2 Simple Ways 5. Tips to Prevent Mould from Returning 6. FAQs About a Moldy Mattress

The Dangers of Mould

Mould is more than just an ugly stain or musty smell—it’s a living fungus that releases spores into the air. These spores can cause a wide range of health problems, especially when trapped in a small area like your bedroom. Prolonged exposure to a mouldy mattress may cause:

headaches or dizziness
nasal congestion or sinus infections
coughing, wheezing, or breathing discomfort
irritated skin
worsened asthma or allergies

According to the Australian Department of Health, mould can grow anywhere with moisture, warmth, and poor airflow—three things that often describe the inside of a mattress.

Sleeping on a mouldy mattress means you are breathing in harmful spores for hours every night, which is why early detection and removal are essential.

How Mould Forms on a Mattress

Mould doesn’t appear overnight. It forms slowly as moisture becomes trapped inside the mattress layers. The most common causes include:

1. Excess humidity

Areas like Brisbane, Sydney, Cairns, and other coastal regions naturally experience high humidity. Mattresses easily absorb moisture from the air, creating the perfect environment for mould to grow.

You can place a dehumidifier in your home to regularly remove excess moisture from the air.

2. Night sweats and body heat

Sweat, body oils, and heat create the perfect environment for mould growth—especially in memory foam or latex mattresses.

3. Poor ventilation

If your mattress sits directly on the floor or on a solid base without airflow, trapped moisture has nowhere to go.

4. Spills or accidents

Liquid spills—even small ones—can seep deep into the mattress and encourage mould if not dried thoroughly.

5. Lack of sunlight

Dark, cool bedrooms can trap moisture. Without sunlight, mould can grow quickly on both the surface and inner layers.

6. Old mattress materials

Older mattresses tend to retain moisture more easily, especially if the foam has started to break down. An average mattress has a lifespan of about 8–10 years. When a mattress is used for too long, trapped sweat and moisture can accumulate inside, creating an ideal environment for mould growth and other hygiene issues.

Understanding how mould forms helps you prevent future issues—and ensures you know exactly what to look for.

5 Signs Your Mattress Has Mould

Spotting mould early can save both your mattress and your health. Here are the most common symptoms:

1. Musty or Damp Smell

This earthy, sour smell is often the very first sign of mould—even before any visible growth appears on the mattress.

2. Discoloured Spots or Stains

Check your mattress for unusual patches in colours such as green, grey, black, brown, or yellow. These stains may show up on the surface, along the seams, or in hidden areas.

3. Increased Allergies at Night

If you notice itchy eyes, sneezing, a stuffy nose, or coughing when you wake up, mould spores from the mattress may be the cause.

4. Mattress Feels Damp or Cold

A mattress that never feels completely dry—even with good airflow—may have trapped moisture inside the layers, which is an early indicator of mould growth.

5. Mould on Your Bedroom Walls

If mould has started to appear on your bedroom walls, there’s a high chance your mattress also has mould growing on it.

Mould vs. Mildew on Your Mattress

Although people often mix them up, mould and mildew aren’t the same—and knowing the difference helps you identify the problem faster.

Mould

Usually appears green, black, or dark brown.
Has a fuzzy or patchy texture.
Penetrates deeper into the mattress materials.
Causes stronger odours and may trigger allergies or respiratory irritation.
Harder to remove and often indicates long-term moisture exposure.

Mildew

Appears white, grey, or light yellow.
Looks powdery or flat, usually sitting on the surface.
Easier to clean because it doesn’t sink as deeply into the foam.
Typically forms during the early stages of moisture buildup.

If you see dark fuzzy patches or smell a strong musty odour, you’re most likely dealing with mould—not mildew—and it requires immediate cleaning (or mattress replacement if the growth is severe).

How to Remove Mould in 2 Simple Ways

Cleaning mould or mildew from a mattress isn’t difficult, and the steps are straightforward. However, before you begin, there are a few important preparations you need to make.

Please Note:

If mould on your mattress is severe and reappears shortly after cleaning, it likely means the mould has already penetrated deep into the mattress. In this case, it’s best to replace the mattress or contact a professional mould removal service.

How to Prepare for Mattress Mould Removal?

Work in a well-ventilated area or bring the mattress outside.
Wear gloves, a mask (P2/N95 if available), and eye protection.
Do not soak the mattress — excess liquid can drive mould deeper into the foam.
Test any cleaning solution on a small hidden area first to check for discolouration.
If mould covers a large area (>30%) or returns after cleaning, it’s safer to replace the mattress or hire professional mould removal services.

How to Remove Mould from Mattress with Rubbing Alcohol?

Step 1. Prepare & Vacuum: Move the mattress to a well-ventilated area and vacuum the surface to remove loose mould spores.
Step 2. Mix & Test: Combine rubbing alcohol and water (1:1) in a spray bottle, then spot-test on a hidden area to ensure no damage or discoloration.
Step 3. Clean the Mould: Lightly spray the solution on the mouldy spots and gently scrub with a soft brush or cloth. Avoid soaking the mattress. Blot with a clean, dry cloth.
Step 4. Baking Soda (Optional): Sprinkle baking soda over the treated area to absorb odors and moisture. Leave it for 8–12 hours, then vacuum off the baking soda and any residue.
Step 5. Dry & Deodorise: Allow the mattress to fully dry in sunlight or with a fan/dehumidifier before using.

How to Clean Mold from Mattress with Hydrogen Peroxide?

Step 1. Prepare & Vacuum: Take the mattress outside or ensure the room is well-ventilated, then vacuum thoroughly to remove loose mould spores.
Step 2. Test First: Apply a small amount of 3% hydrogen peroxide to a hidden area to check for any bleaching or discoloration before full application.
Step 3. Treat the Area: Lightly spray hydrogen peroxide on the mouldy spots, let it bubble for 5–10 minutes, then gently scrub with a soft brush and blot dry with a clean cloth.
Step 4. Baking Soda (Optional): Sprinkle baking soda over the treated area to absorb odors and moisture. Leave for 8–12 hours, then vacuum off the baking soda and any residue.
Step 5. Dry Completely: Allow the mattress to air-dry fully in sunlight or use a fan/dehumidifier until it is completely dry before using.

Tips to Prevent Mould from Returning

If you can prevent mould growth on your mattress from the start, you’ll save yourself a lot of trouble. Once you’ve cleaned the mould, the next step is to prevent it from coming back. Beacause proper prevention not only keeps mould away but also extends the lifespan of your mattress.

1. Use a waterproof mattress protector

It blocks sweat, spills, and humidity from penetrating the foam.

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2. Maintain good airflow under your bed

Avoid placing your mattress directly on the floor.

3. Air your mattress regularly

Expose it to sunlight a few times a month if possible.

4. Keep humidity below 50%

Use a dehumidifier in humid climates like Queensland or coastal NSW.

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5. Wash bedding weekly

Damp sheets can transfer moisture into your mattress.

6. Flip or rotate your mattress

This helps even airflow and prevents moisture buildup in one spot.

7. Clean spills immediately

Even small spills can create hidden moisture pockets.

FAQs About Moldy Mattress

1. Can I sleep on a moldy mattress?

No. Sleeping on a mouldy mattress exposes you to allergens and spores that may trigger coughing, sneezing, headaches, skin irritation, or even respiratory issues. It’s best to clean the mould immediately or replace the mattress if the infestation is severe.

2. Will hydrogen peroxide or rubbing alcohol damage my mattress?

Using either product can potentially harm your mattress depending on how it’s applied. Hydrogen peroxide may lighten fabrics or break down foam if used excessively, while rubbing alcohol can weaken materials over time and is highly flammable. To stay safe, apply only a small amount, patch-test on a hidden spot first, and never mix these cleaners with other chemicals.

3. How long does it take for mould to grow back after cleaning?

If moisture isn’t controlled, mould can return within days. Use a dehumidifier, ensure your room is well-ventilated, and keep the mattress dry to prevent recurring issues.

4. When should I replace a mouldy mattress?

If the mould has spread deeply, has a strong smell that won’t go away, or keeps reappearing after cleaning, it’s safer to replace the mattress — especially for children, elderly people, or anyone with asthma or allergies.

5. Does sunlight kill mould on mattresses?

Direct sunlight helps dry out moisture and can reduce surface mould, but it doesn’t always kill mould deep inside the foam. Use sunlight as part of the cleaning process, not the only solution.

Botton Lines

With the right steps, you can remove mould on a mattress safely and prevent it from coming back. Remember: mould grows silently, so early detection is key. If you live in a humid area, take extra precautions—regular airflow, sunlight, mattress protectors, and routine cleaning all make a huge difference.

Your bedroom should be a healthy, breathable space where you can sleep soundly every night. With a little effort and the right techniques, you can restore freshness to your mattress and keep mould away for good.