Mold on Leather: How to Clean Shoes, Jackets and Couches

Leather is skin, and mold likes it. The National Park Service's conservation guidance says leather is particularly susceptible to mold and can be stained and weakened by it. It groups leather with other protein-based materials that are particularly susceptible to direct attack by microorganisms.

Humidity is the trigger. The Canadian Conservation Institute (CCI) says relative humidity (RH) between 65 and 100%, warm temperatures, and poor air circulation promote mould growth, and gives a rough timeline:

How fast mold grows on leather at different humidity levels (CCI)

Source: CCI Notes 8/1, "Generally mould will grow after two days at 90–100% RH, 10 days at 80% RH and 100 days at 70% RH."

Oils and conditioners can make it worse. The NPS says dressings can trap moisture in the fibers of the leather and create the ideal environment for mold, and that many fungi feed on animal fats and thrive in humid conditions.

Not every white film on leather is mold. Oils and waxes in leather can rise to the surface as a whitish bloom, called spew. The NPS explains how to tell them apart: mold has a branched, soft or fuzzy appearance, while spew has distinct edges. It also suggests a test: put the item in low humidity (below 50 percent), and actively growing mold should shrivel.

If there's a musty smell, treat it as mold. CCI's rule is simple: if in doubt, treat as a mould covered object.

CCI says mould is a serious health concern and that people with allergies, respiratory conditions or weakened immune systems should avoid handling it. For small jobs it recommends an N95 or N100 respirator, disposable gloves and non-vented goggles. The CDC also says do not touch mold or moldy items with bare hands.

Work outdoors. University of Georgia Extension's flood guide says to clean mildewed items outside to avoid spreading mold spores inside.

These steps combine conservation guidance from CCI and the National Park Service with University of Georgia Extension's upholstery steps, which list leather among the covered materials.

1. Bag it and move it

CCI suggests you isolate the infested object by sealing it in a plastic bag or container so spores don't spread to other things in the closet. Don't leave it sealed for long if it's damp: CCI warns that if left in a sealed bag the mould will grow.

2. Dry it before you clean it

If the leather is wet or damp, CCI says it should be dried as quickly as possible, outdoors on a clear, dry day or in a well-ventilated space. Avoid strong heat: the NPS cautions that heat from a hair dryer may also cause the leather to shrink.

You'll know it's dry enough when the mold brushes off as powder. CCI notes that if the mould smears, the leather or skin may not be dry enough to clean.

3. Vacuum the dry mold off

Use a vacuum with a HEPA filter; CCI says one is strongly recommended. Vacuum the whole item, not just the spots you can see. CCI suggests going over it twice, in perpendicular directions, and using a soft brush to direct mould that is otherwise difficult to remove toward the nozzle. The NPS adds: use the lowest effective suction, and only vacuum mold that's dry and powdery.

Seal the vacuum bag or filter contents in a plastic bag and put it in the outside trash.

4. Wipe remaining marks with diluted alcohol

For marks left after vacuuming, UGA Extension's upholstery guidance (which covers leather) suggests a cloth moistened with 1 cup denatured or rubbing alcohol and 1 cup water, then blotting and drying, in sun and air if possible. UGA says to pretest each cleaning agent on an inconspicuous area first. Use a damp cloth, not a wet one.

5. Decide about conditioner

This is where advice splits:

• Everyday items. UGA Extension's leather steps end with a commercial leather conditioner, which it says will return oil to the leather and will prevent cracking. If you use one, apply a thin coat and wipe off the excess.
• Heirlooms and antiques. Conservators disagree. The NPS advises caretakers to refrain from dressing leather, and CCI says research has shown dressings are generally not effective in preserving leather. CCI also says saddle soap is very alkaline, which causes degradation of the leather on older stiff leathers.

Whichever you choose, heavy oiling in a humid house invites mold back.

6. Dry, then watch it

Let the item air out fully before it goes back in the closet. Check it again in a week. Regrowth means it was still damp or the storage spot is too humid.

What not to use: chlorine bleach (it damages leather), and never mix cleaning products. The EPA warns to never mix chlorine bleach solution with other cleaning solutions or detergents that contain ammonia.

Shoes are the most common moldy leather item. Clean them with the steps above, paying attention to seams, tongues and the inside, and let them dry fully before they go back in the closet.

UF/IFAS Extension's mildew advice includes a simple rule: keep shoes dry and clean. After a flood, UGA Extension says you must dispose of items with foam padding, like bras and shoes.

Follow the step-by-step method above, outdoors, with the lining checked as well as the outside. A fabric lining can usually be cleaned like other fabric; our mold on clothes guide covers washable fabrics. For suede, expensive pieces or anything with a stubborn stain, a professional leather cleaner is the safer bet.

After a flood, UGA Extension warns that you may also need to throw away wool or leather items.

A leather couch has two parts: the leather cover, which you can usually clean with the steps above, and the foam and fabric inside, which you often can't. The EPA lists upholstered furniture among items that may be difficult to completely dry within 48 hours, and suggests a furniture restoration professional for valuable pieces.

If mold is only on the surface, vacuum and wipe it, then dry the room. If the cushions smell musty from the inside, or the couch got soaked, the padding is the problem. After a flood, Texas A&M AgriLife Extension says to discard flooded padding. Our mold on furniture guide covers sofas and upholstery in more detail.

For anything irreplaceable, call a conservator before you clean. The NPS recommends that you contact a conservator for assistance in dealing with the infested material, and notes that chemical treatments can themselves damage objects. CCI's advice for anything uncertain is to check with a conservator.

• Keep humidity in range. CCI says mould requires a relative humidity in excess of 65% to grow and recommends a stable RH of 45 to 55 percent. For your whole house, the EPA recommends below 60 percent (ideally between 30 and 50 percent). A dehumidifier for mold helps in a damp closet.
• Keep air moving. CCI says adequate RH controls and air circulation will prevent its outbreak. Don't cram jackets together.
• Avoid damp spots. The NPS advises avoiding storage in or near damp areas such as attics, basements, sinks, windows, or directly on floors. In Texas, an uncooled garage or attic is a bad place for leather.
• Breathable covers, not sealed plastic. CCI suggests polyethylene or cotton dust sheets for dust protection, and Kentucky Extension advises that items should never be stored in airtight plastic.
• Never put leather away damp.

If several items in one closet keep molding, the closet is the problem, not the leather. Look for a wet wall, a leak or condensation. Our guides on signs of mold in house and mold smell in house can help.

For hidden mold, a licensed mold testing company in Dallas, Houston or another city on our Texas page can inspect. Cleanup of walls and building materials goes to a separate mold removal company: Texas law says a license holder may not perform both mold assessment and mold remediation on the same project. Check licenses with our license check tool.

If you have symptoms you think are tied to mold, see a doctor; a mold test can't diagnose illness. The CDC says individuals with persistent symptoms should see their physician.