Prep first
Before you start
- Fix the damp first: wool dried within 24 to 48 hours usually won't grow mold again.
- Wear gloves, goggles without vents, and an N-95 respirator so you don't breathe in or touch spores.
- Take the wool outside before you start, if you can, so spores don't scatter through the house.
Mold on wool is a living fungus that takes hold on fabric that stayed damp, and the dark mark it leaves is partly damage to the fibers themselves. Fresh growth often lifts out with gentle suds and full drying, but an old stain can weaken the wool so much that it won't come out completely. Go slowly, because scrubbing hard can thin the fibers even further.
If you're trying to get musty smell out of wool sweaters, wash gently and let the piece dry fully before you judge the result. Skip wringing and hard rubbing, since that thins the fibers even more. If the mold is old or won't budge, reach for a delicate laundry detergent, and call a professional if it still won't lift.
Before you start
What wool & cashmere can take
Use with care4
- Water
- Soaking
- Solvents (alcohol, spot removers)
- Acids (vinegar, lemon)
Avoid6
- Hot water
- Chlorine bleach
- Oxygen bleach
- Enzyme cleaners
- Scrubbing and abrasives
- Heat, once the stain is out
8 items
What you'll need
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- Mild liquid dish soapMakes the suds for the hand wash and is the base of the spot treatment. (opens Amazon)
- GlycerinThe base of the spot-treatment mix. (opens Amazon)
- White vinegarA few drops go into the spot-treatment mix, and only white. (opens Amazon)
- Vacuum with an attachmentDraws loose spores out of the surface before any water touches it.
- Sponges and clean clothsLift the suds and rinse the wool without rubbing it. (opens Amazon)
- Absorbent padLets you work the spot treatment into the mark without soaking the wool around it.
- Clean towelGives the wool a flat, dry surface to dry on.
- Gloves, goggles without vents, and an N-95 respiratorKeep spores off your skin and out of your lungs. (opens Amazon)
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6 steps
Step by step
Step 1 of 6
Shake out the loose mold
Take the wool outside if you can, and shake it gently to knock loose mold off the surface. Then run a vacuum attachment over the fabric to draw out more spores before any water touches it.
Careful. Don't rub or brush the stain itself. Lift the spores with shaking and the vacuum instead.
Step 2 of 6
Mix a thick suds bath
Put a mild liquid dish soap in a bowl of lukewarm water, about 30°C, and swish it hard until you have thick suds. Keep the bath at that temperature for the whole wash.
Step 3 of 6About 10 minutes
Soak, then sponge the suds on
Let the wool soak in the suds for about 10 minutes, as you would in a hand wash. Then sponge the thick suds over the stained area, working gently and dabbing rather than rubbing.
Step 4 of 6
Sponge out the suds
Remove the suds by sponging with a cloth or sponge dampened with clean water. Change to fresh water as it clouds, and keep going until no soap is left on the fabric.
Step 5 of 6
Dry it flat in the sun
Lay the wool flat on a clean towel and dry it in direct sun if you can, since 1 or 2 days of sunlight kills mold spores. Turn it once or twice so the underside dries as well.
Careful. Don't tumble dry wool unless the label says 'tumble dry'.
Step 6 of 6
Spot-treat any stain that remains
Mix 1 part glycerin, 1 part white dishwashing detergent, and 8 parts water, then add a few drops of white vinegar. Apply it to the mark with an absorbent pad, then sponge with clean water and dry flat.
Tip. Work from the edge of the mark toward the center so it doesn't spread.
If you'd rather buy than mix
Best products for mold on wool & cashmere
Use a mild liquid dish soap for the suds, and a plain glycerin for the spot-treatment mix. If you need alcohol, choose 70% isopropyl or 90% denatured with no added color or fragrance, and skip any product that lists bleach or enzymes on the label.
Woolite Delicates
How we picked these: each product is made for this type of stain, its maker doesn't warn against using it on wool & cashmere, and its directions fit the steps above.
Finished the steps? How does it look?
Nice work. Let it dry completely and check it again in good light before using any heat. Here is what done looks like:
How to tell it's really gone →A faint mark usually needs one more round, not a stronger product.
Heavy buildup usually takes more than one round.
Heavy or long-standing buildup →When to call a professional →How to tell it's working
The musty smell should fade as the wool dries, and the rinse water should look cleaner with each sponge-out. If the smell is still strong once the wool is fully dry, move on to the spot treatment rather than repeating the suds.
What changes for yours
Adjust for your wool & cashmere
Sweaters and blankets
Sweaters need the most care in handling, since a wet knit can stretch under its own weight. Lift the sweater out of the suds with both hands, and don't wring a cashmere piece; squeeze it gently instead.
Blankets hold more water and take longer to dry, so expect the full 1 to 2 days. Lay a blanket flat, and turn it so the underside dries too.
Wool area rug
A rug needs more air than clothes do, so open draperies to let sunlight reach it and run a dehumidifier and fans. Allow 1 or 2 days of direct sunlight to kill the spores, and lift the rug if you can so air moves underneath it.
Run a vacuum attachment over the surface first to draw out more mold, then sponge with suds as in the main method. Keep the water light, because too much can leave a ring that is hard to erase, and let the back dry fully before you lay the rug down.
Heavy or long-standing buildup
Old mildew stains are harder to lift than fresh ones, and some won't respond at all. On wool, a stain that has sat for a long time has often weakened the fibers, so a badly damaged piece may not clean at all. Work with the lightest touch you can, because mildew weakens the fibers further with every pass.
Once the stain has dried, repeat the spot-treatment mix as many times as it takes, and move to the dry spotter mix only if the mark stays. Use the dry spotter mix sparingly and sponge it out with water afterward, so the solvent doesn't spread past the mark.
Heat from a dryer can set a dye-transfer stain, so expect only partial improvement after that. If the mark still shows after the home steps, a professional dry cleaner is the realistic next step. On an old or heirloom piece, removing a long-standing stain can leave a hole, so it may be wiser to leave it alone.
Vinegar, baking soda, peroxide and more
Do home remedies work on mold on wool & cashmere?
Most home remedies for mildew on wool are too harsh for wool or built for other stains, so only a few make the cut. For yarn you'd rather not wash, shake it out outdoors and air it in a dry, breezy spot until the smell fades. If it stays, use the gentle hand wash in the main method.
Works2Helps1Skip1Avoid2
What makes it worse
Mistakes to avoid
Don't skip the test patch.
Always pretest each cleaner on a hidden seam or the inside hem to check colorfastness. Vinegar can change the color of some dyes, so test the spot-treatment mix the same way.
Don't use bleach or oxygen-bleach products on wool.
Chlorine bleach is a no for wool, silk, mohair and spandex, and oxygen-bleach stain removers are a no for wool and wool blends. Enzyme detergents are out too, so stick with the mild dish soap in the main method.
Don't reach for ammonia.
Ammonia damages wool, so leave it out of every mix, including the upholstery-style recipes you may find online. Never mix ammonia with chlorine bleach, because toxic fumes can form.
Don't use hot water.
Keep the water lukewarm, about 30°C, from the suds through the final sponge. Hot water is a no for wool, even when the stain looks stubborn.
Don't store wool that's still damp.
Water is what mold needs, so wool that goes into a closet or drawer before it's fully dry can grow mold again. Check the seams and the underside before you put it away.
When to call a professional
Use a professional dry cleaner if the label says dry clean only, if a hidden-area test shows color transfer or change, or if a stain stays after home treatment. Dry cleaning is the preferred method for wool because it keeps shrinkage down.
Questions
Can I get a musty smell out of wool yarn without washing it?
You can start by shaking it out outdoors and airing it in a dry, breezy spot until the smell fades. If it still smells after that, wash it gently by hand in lukewarm water, since the mildew may still be in the fibers.
Does a musty smell in wool always mean mold?
Not always, but a musty smell usually means mildew has started, often from wool that stayed damp too long. Dry it completely, then clean it with the hand wash.
Can I wash mildewed wool in the washing machine?
Hand washing is the safer choice. Use lukewarm water, about 30°C, with a mild detergent, and don't agitate the wool, since agitation makes it felt and shrink.
What should I do about mold in the closet where the wool was stored?
Fix the moisture in the closet first, since mold can't grow without it. Then take the wool outside to shake it out and dry it in direct sun for 1 or 2 days.
Will the mildew stain come out completely?
Sometimes not. The mark is often damage to the fibers, so it may not fully lift even when the smell is gone.
How long does wool take to dry after cleaning?
Plan on 24 to 48 hours for a wet area to dry fully. Direct sun for 1 or 2 days also helps kill any spores that are left.
Mold on other materials
Other stains on wool & cashmere
Start from the bigger picture
How we know this
Every method, amount and warning here comes from university extension services, industry bodies and product makers. We read them, check every step for unsafe combinations and changed amounts, and write it up so you can follow it.