Why Does Mould Grow on Leather?

Leather is a natural, porous material that absorbs moisture readily — making it one of the more common surfaces affected by mould in Australian homes. Shoes, bags, jackets, sofas, car seats, and belts are all susceptible, particularly when stored in humid or poorly ventilated conditions.

Mould thrives on leather because:

• Leather retains moisture — especially when stored in humid environments or after getting wet
• It's an organic material — the natural oils and proteins in leather provide nutrients for mould spores
• Poor ventilation accelerates growth — wardrobes, shoe cupboards, and storage boxes with limited airflow are high-risk zones
• Infrequent use — items left undisturbed for long periods are more likely to develop mould undetected

In Australia's humid coastal and subtropical climates, leather mould is a particularly common problem during summer and after periods of heavy rain.

How to Identify Mould on Leather

Mould on leather can be easy to miss in its early stages. Look for:

• White or grey powdery coating — often the first sign, sometimes mistaken for dust or salt bloom (efflorescence)
• Green, black, or blue-green patches — indicating more established mould colonies
• Musty smell — a reliable early indicator before visible growth appears
• Sticky or tacky surface texture — mould can affect the leather's finish and feel

Note: White powdery residue on leather can sometimes be natural fats migrating to the surface — rather than mould. If it wipes away cleanly with a dry cloth and there's no musty odour, it may not be mould. If in doubt, treat it as mould to be safe.

Health Risks

Mouldy leather items, particularly those used frequently like car seats or sofas, can continuously release spores into your living environment. This can contribute to:

• Respiratory irritation and chronic coughing
• Allergic reactions including skin rashes and eye irritation
• Aggravated asthma and sinus conditions
• Headaches and fatigue in heavily affected spaces

Address mould on leather promptly, especially on items used in enclosed spaces like cars.

How to Remove Mould from Leather

Leather requires a gentler approach than hard surfaces — harsh chemicals and excessive moisture can dry out, crack, or permanently stain the material. Here's how to do it safely.

Step 1: Take It Outside

Always treat mouldy leather outdoors to avoid spreading spores inside. Wear gloves and, for significant growth, a P2 respirator mask.

Step 2: Brush Off Loose Mould

Use a soft-bristled brush or dry cloth to gently remove loose surface mould. Work carefully to avoid spreading spores or scratching the leather surface.

Step 3: Apply a Mould Remover

Use a mould remover that is safe for use on leather and fabric surfaces. Avoid bleach-based products — they will strip colour, dry out the leather, and cause cracking over time.

Green Goo's Eco Sentinel is formulated to kill mould at the source without damaging delicate surfaces. Apply sparingly to a soft cloth rather than spraying directly onto the leather, then gently work it into the affected area.

Step 4: Wipe Clean

Use a clean, damp cloth to wipe away the treated area. Avoid saturating the leather with water — use as little moisture as possible.

Step 5: Allow to Dry Naturally

Let the leather dry at room temperature, away from direct sunlight or heat sources (which can cause cracking). Do not use a hairdryer or place near a heater.

Special Considerations by Leather Type

Leather Shoes & Boots

Store shoes with cedar shoe trees to absorb moisture and maintain shape. Ensure shoes are fully dry before storing, and keep them in a ventilated area rather than sealed boxes.

Leather Sofas & Furniture

Leather furniture in humid rooms benefits from regular wiping with a dry cloth and periodic conditioning. Ensure the room is well-ventilated and consider a dehumidifier in high-humidity areas.

Car Leather Seats

Cars can trap humidity, particularly in coastal areas. Park in ventilated areas where possible, and treat any mould promptly to prevent it spreading to other interior surfaces.

Leather Bags & Accessories

Store leather bags stuffed with tissue paper (not newspaper, which can transfer ink) in breathable dust bags — not plastic. Avoid storing in sealed wardrobes without airflow.

Preventing Mould on Leather

A few simple habits go a long way in keeping leather mould-free:

• Keep leather dry — dry items thoroughly after exposure to rain or moisture before storing
• Store in ventilated spaces — avoid airtight containers and poorly ventilated wardrobes
• Use silica gel sachets — place these in shoe boxes, bags, and storage areas to absorb excess moisture
• Condition regularly — well-conditioned leather is more resistant to moisture absorption
• Air items out periodically — even stored leather benefits from being aired in a dry, well-ventilated space
• Apply a preventative mould inhibitor — a light application of mould prevention spray on at-risk items at the start of humid seasons can stop spores from taking hold

The Green Goo Approach

At Green Goo, we know that mould doesn't discriminate — it will grow on almost any surface given the right conditions. Our eco-friendly mould removal products are designed to be effective across a wide range of surfaces, including leather and fabric, without the harsh chemicals that cause damage.

If you're dealing with mould on leather shoes, furniture, or accessories, Green Goo offers a safe, effective solution. Explore our full range of mould removers, concentrates, and refills — and protect the things you love.