How to Remove Mildew from Upholstery
Mildew on upholstery is more than an odor problem: it can stain fabric, damage fibers, and spread quickly if moisture remains.
This guide explains how to remove mildew from upholstery safely, which cleaning methods work best by material, and how to prevent it from returning.
What mildew is and why upholstery gets it
Mildew is a surface fungus that grows in damp, poorly ventilated areas.
Upholstery becomes vulnerable after spills, leaks, high humidity, wet clothing, or long periods in storage.
Sofas, armchairs, cushions, car seats, and ottomans are especially at risk because foam padding can trap moisture below the surface.
Unlike ordinary dirt, mildew can create a musty smell and leave gray, green, or white patches.
If left untreated, it may spread deeper into the fabric or padding, making removal harder and increasing the chance of permanent damage.
Before you clean: identify the upholstery material
The safest method depends on the fabric type.
Check the care tag first, because the manufacturer’s cleaning code can prevent accidental damage.
- W: clean with water-based products.
- S: use solvent-based cleaners only.
- WS: use either water-based or solvent-based products.
- X: vacuum only; professional cleaning is usually recommended.
If the upholstery is leather, suede, velvet, silk, or has an X code, use extra caution and consider a professional cleaner.
Always test any solution on a hidden area first.
Supplies you may need
- Vacuum with upholstery attachment
- Soft-bristled brush
- Microfiber cloths
- Spray bottle
- White vinegar or rubbing alcohol
- Mild liquid soap
- Baking soda
- Fan or dehumidifier
- Gloves and a mask
For severe mildew or valuable furniture, a professional upholstery cleaning service may be the safest option.
How to remove mildew from upholstery safely
1. Move the item to fresh air
If possible, take the furniture outdoors or into a well-ventilated area.
This helps reduce spores and speeds drying.
Avoid cleaning in a closed room, because excess moisture can worsen the problem.
2. Vacuum loose spores
Use a vacuum with an upholstery attachment to remove surface mildew, dust, and debris.
Work gently so spores are not driven deeper into the fabric.
Empty the vacuum canister or replace the bag afterward to avoid cross-contamination.
3. Dry-brush the affected area
With a soft brush, loosen visible mildew growth.
Brush lightly and use short strokes.
If the fabric is delicate, skip this step and proceed directly to testing a cleaner.
4. Apply the right cleaning solution
For many washable fabrics, a diluted white vinegar solution is an effective first choice.
Mix equal parts white vinegar and water in a spray bottle, lightly mist the area, and let it sit for 10 to 15 minutes.
Then blot with a clean cloth.
For more stubborn mildew on durable fabric, a small amount of rubbing alcohol can help.
Use 70% isopropyl alcohol on a cloth or dilute it slightly with water, then dab the area.
Do not soak the upholstery.
If the care tag allows water-based cleaning, you can also use a small amount of mild dish soap mixed with warm water.
Apply foam or a lightly dampened cloth rather than pouring liquid directly onto the fabric.
5. Blot and lift, don’t scrub
Scrubbing can spread mildew, damage fibers, and push moisture into the cushion.
Instead, blot the area repeatedly with a dry microfiber cloth until the surface is as dry as possible.
Replace cloths as they become damp.
6. Deodorize with baking soda
After the area is mostly clean and dry, sprinkle baking soda over the upholstery to help absorb odor.
Let it sit for several hours or overnight, then vacuum thoroughly.
This step works well on sofas, cushions, mattresses, and car upholstery.
7. Dry completely
Drying is critical because leftover moisture encourages mildew to return.
Use fans, open windows, or a dehumidifier.
If possible, place the furniture in sunlight for a short period, but avoid prolonged direct sun on delicate fabrics, which can fade colors.
How to remove mildew from upholstery by material
Fabric upholstery
Fabric upholstery usually responds best to vinegar, mild soap, and thorough drying.
If the mildew is only on the surface, vacuuming and spot cleaning may be enough.
For cushions with removable covers, wash them only if the care label permits machine washing.
Microfiber upholstery
Microfiber is often durable, but it can still hold moisture in the pile.
Use a very light application of vinegar solution or rubbing alcohol, then brush the fibers gently after drying to restore texture.
Leather upholstery
Leather should not be saturated with water or vinegar.
Wipe the surface with a barely damp cloth, then use a leather-safe cleaner or a solution recommended by the manufacturer.
After cleaning, condition the leather to help prevent cracking.
Suede and velvet
Suede and velvet are more difficult to clean safely at home.
A dry brush and vacuum may remove light mildew, but liquid cleaners can leave marks.
If the stain is noticeable or widespread, professional cleaning is often the best choice.
When mildew has reached the cushions or padding
If the smell returns after surface cleaning, the mildew may have penetrated the cushion filling.
In that case, remove covers if possible and inspect the foam or batting.
Mild cases can sometimes be treated with careful drying and deodorizing, but deeply affected padding often needs replacement.
Do not seal a damp cushion inside a cover or storage bag.
Trapped moisture creates ideal conditions for regrowth and can spread the problem to surrounding furniture.
What not to do when cleaning mildew
- Do not saturate upholstery with water.
- Do not mix bleach with vinegar, ammonia, or other cleaners.
- Do not use harsh bleach on most fabrics or leather unless the manufacturer specifically approves it.
- Do not use excessive heat, which can set stains or damage fabric backing.
- Do not store furniture before it is completely dry.
How to prevent mildew from coming back
Prevention is mostly about controlling moisture and improving airflow.
Keep indoor humidity below 50% if possible, especially in basements, closets, and vacation homes.
Use a dehumidifier in humid climates and run fans after spills or deep cleaning.
Also inspect upholstery after leaks, roof damage, plumbing issues, or long periods of storage.
Clean spills quickly, rotate cushions regularly, and avoid placing furniture directly against cold, damp walls.
For car interiors, leave windows open briefly on dry days and use moisture absorbers when needed.
When to call a professional cleaner
Professional help is a smart choice if the mildew covers a large area, keeps returning, or affects antique, high-value, or delicate upholstery.
Experts can assess whether the issue is limited to the surface or has reached the padding, and they have tools for deep extraction, odor treatment, and controlled drying.
If you see widespread discoloration, persistent musty odor, or signs of water damage inside the frame, a professional upholstery cleaner or restoration specialist can prevent further loss.