Wash the blanket in hot water with vinegar or bleach
The fastest way to kill mold on a blanket is a hot-water wash with either white vinegar or chlorine bleach. Hot water alone kills many mold spores, but the vinegar or bleach makes sure you get the rest. Use one cup of white vinegar or half a cup of bleach per load, depending on the blanket's fabric—bleach works faster but can fade colors, while vinegar is gentler and works on most materials.
Check the blanket's care label first. If it says "bleach safe" or shows a triangle symbol, bleach is your safest choice. If the label warns against bleach or the blanket is colored, use vinegar instead. Wash on the hottest water temperature the label allows, usually 130°F or higher, because mold dies at sustained heat above 140°F.
Run the blanket through a full wash cycle, then dry it when ready on high heat in the dryer or in direct sunlight outdoors. Do not let it sit damp in the washer—mold can regrow within 24 to 48 hours in a moist environment.
Key Takeaways
- Hot water combined with vinegar or bleach kills mold spores during washing; use one cup of vinegar or half a cup of bleach per load.
- Check the care label to decide between bleach (faster, may fade colors) and vinegar (gentler, works on most fabrics).
- Dry the blanket when ready on high heat or in direct sunlight to prevent mold from regrowing in damp fabric.
- If mold returns after washing, the blanket may have absorbed moisture from the air or storage location, and you will need to address the environment.
- Blankets with deep mold staining or musty odor that does not wash out may be too damaged to save and should be discarded.
Why mold grows on blankets and where it starts
Mold needs three things: moisture, warmth, and organic material. Blankets provide all three—they are made of cotton, wool, or synthetic fibers that mold feeds on, they absorb moisture from humid air or spills, and they are often stored in warm closets or under beds. Mold usually starts as a small spot where moisture got trapped, often in a fold or corner where air does not circulate.
The most common cause is storing a damp blanket. If you wash a blanket and do not dry it completely, or if you fold it away while it still has any moisture, mold will begin growing within hours. The second most common cause is high humidity in the storage space—basements, attics, and poorly ventilated closets are prime spots. A third cause is a spill or accident that soaked the blanket and was not addressed quickly.
Treating stubborn mold stains and odor
If the blanket still smells musty or shows discolored patches after the first wash, soak it before washing. Fill a bathtub or large basin with hot water and add two cups of white vinegar or one cup of bleach. Submerge the blanket and let it soak for one to two hours, then drain and wash as normal. This gives the vinegar or bleach time to penetrate deep into the fibers where mold may be hiding.
For odor that lingers after washing, add half a cup of baking soda to the rinse cycle or soak the blanket in a solution of one part baking soda to four parts water for 30 minutes before washing. Baking soda neutralizes the musty smell without damaging fabric. If the smell returns after drying, the mold may have penetrated too deeply or the blanket may have absorbed the odor permanently—in that case, the blanket is likely not worth saving.
Do not use fabric softener or scented products to mask the smell. They will not kill the mold, and the smell will return once the product wears off.
Drying methods that prevent mold from returning
The dryer is the most reliable method. Set it to high heat and run it for a full cycle—usually 45 to 60 minutes for a standard blanket. The sustained heat kills any remaining spores and removes all moisture. If your dryer has a moisture sensor, use it; the blanket is done when the sensor detects no more moisture.
Outdoor drying in direct sunlight also works well and costs nothing. Hang the blanket on a clothesline or drape it over a fence in full sun for at least four hours, longer if possible. Sunlight naturally kills mold spores, and the air circulation prevents moisture from being trapped. This method works best on a dry, breezy day; do not hang a blanket outside on a humid or rainy day.
Never air-dry a moldy blanket indoors on a rack or chair. Indoor air is usually humid enough that the blanket will dry slowly, giving mold time to regrow. If you must dry indoors, use a fan pointed at the blanket and keep a window open to move humid air out of the room.
Storing blankets so mold does not come back
Store blankets only when they are completely dry. After washing and drying, let the blanket sit in a warm, dry room for a few hours before folding it away. This ensures any remaining surface moisture evaporates. Fold it loosely rather than tightly—tight folds trap air and moisture in the center of the bundle.
Choose a storage location with low humidity and good air circulation. A bedroom closet with a door that opens regularly is better than a sealed plastic bin in a basement. If you must use a closet, leave the door cracked open or install a small vent to allow air to move through. Basements and attics are risky unless they are climate-controlled and dehumidified.
If your home has high humidity—above 60 percent—consider using a dehumidifier in the storage area or storing blankets in a different room. You can check humidity with an inexpensive hygrometer, available at hardware stores. Do not store blankets in plastic bags or airtight containers; use breathable cotton storage bags or open shelving instead.
When to throw a blanket away instead of washing it
If the mold covers more than a quarter of the blanket's surface, or if the blanket feels stiff or brittle after washing, the mold has damaged the fibers beyond repair. Mold produces acids that break down fabric, and once that damage is done, washing will not restore the blanket's strength or feel.
If the musty smell persists after two washings with vinegar or bleach, the odor has likely soaked into the fibers permanently. A blanket that smells bad will make your bed smell bad, and no amount of washing will fix it. In this case, discard the blanket and start fresh.
Blankets with mold should be thrown away in a sealed bag to prevent spores from spreading to other items during trash collection. Do not donate a moldy blanket—it will spread mold to the recipient's home.
Fixing the moisture problem in your home
If blankets keep getting moldy even after you wash and dry them properly, the problem is not the blanket—it is the air in your home. High humidity creates an environment where mold grows on anything organic, including blankets, clothes, and furniture. Check the humidity level with a hygrometer; if it stays above 60 percent, you need to reduce it.
Run a dehumidifier in bedrooms and storage areas, especially basements. Open windows on dry days to let fresh air circulate. Fix any leaks in the roof, walls, or plumbing that are letting water in. If your bathroom or kitchen gets steamy, run the exhaust fan during and for 20 minutes after showers or cooking. These steps will stop mold from coming back on blankets and other items.
If you live in a naturally humid climate or in a basement apartment, a dehumidifier is not optional—it is the only reliable way to keep blankets and other fabrics from molding. A small portable dehumidifier costs $100 to $300 and will pay for itself by saving your belongings.
Frequently Asked Questions
Can I use bleach on a colored blanket?
Bleach will fade most colors, so check the care label first. If the label says "no bleach," use white vinegar instead—it kills mold just as well but takes longer and is gentler on dyes. Test bleach on a hidden corner of the blanket first if you are unsure.
How long does it take for mold to die in the wash?
Most mold spores die within the first 20 to 30 minutes of a hot-water wash with vinegar or bleach. The full wash cycle ensures any spores hiding in folds or seams are reached. Drying on high heat kills any survivors.
Will vinegar or bleach damage my blanket?
Vinegar is safe on all washable fabrics and will not fade colors. Bleach can fade colors and weaken some fibers over time, so use it only on white blankets or those labeled bleach-safe. Both are safe when used at the recommended amounts.
What if the blanket still smells musty after I wash it?
Soak it in vinegar or bleach solution for one to two hours before washing, then add baking soda to the rinse cycle. If the smell returns after a second wash, the odor has soaked into the fibers permanently and the blanket should be discarded.
Can I prevent mold by storing blankets in plastic bags?
No—plastic bags trap moisture and create the exact environment mold needs to grow. Use breathable cotton storage bags or open shelving instead, and store blankets only in dry locations with good air circulation.