How to remove mildew and mold stains from fabric and surfaces

How to remove mildew and mold stains

1. 1

   Protect yourself and work outside if you can

   Put on gloves, goggles without vent holes and an N-95 respirator. Take movable items outdoors and shake or brush off the loose growth there.

   Why: Brushing releases spores, and doing it outdoors keeps them out of the house and out of your lungs.

2. 2

   Pretreat dark spots on fabric

   Work heavy-duty liquid detergent or an enzyme detergent into the darkest spots.

   Why: Detergent loosens the soil and organic residue the fungus was feeding on.

3. 3

   Wash hot with a fabric-safe bleach

   Launder in the hottest water safe for the fabric with heavy-duty detergent and chlorine bleach if the label allows. For colors, soak in hot water with oxygen bleach, then launder.

   Why: Hot water and detergent remove the growth, and bleach oxidizes the dark pigment left in the fibers.

4. 4

   Scrub hard surfaces with detergent and water

   On tile, sealed counters, appliance interiors and other hard surfaces, scrub the mold off with detergent and water. For stained cement grout, the American Cleaning Institute uses ¾ cup of chlorine bleach per gallon of water, brushed on and rinsed thoroughly.

   Why: The EPA's rule is to physically remove mold from hard surfaces. Killing it isn't enough, because dead mold can still stain and cause allergic reactions.

5. 5

   Dry completely

   Dry fabric in the sun or, once the stain is gone, in a hot dryer if the label allows. Wipe hard surfaces dry and run a fan or open a window.

   Why: Mold needs moisture. The EPA says drying wet items within 24 to 48 hours usually prevents growth.

6. 6

   Fix the moisture source

   Run the bathroom fan during and after showers, leave shower doors and dishwasher or washer doors ajar, and repair leaks.

   Why: Without that, mold comes back in the same spot. The EPA notes that ventilation and more frequent cleaning usually stop bathroom mold from recurring.

Why mildew stains outlast the mold

Mildew and mold are fungi. On fabric, carpet, grout and caulk they feed on natural fibers, soil, soap film and finishes, and they need moisture to grow. That makes mildew a biological stain: it's alive, and it can keep spreading.

The stain is part pigment and part damage. Texas A&M AgriLife explains that the color of a mildew stain on fabric is partly the shadow of pits the fungus has eaten into the fiber surface. That's why a mark can stay after the mold is gone, and why badly mildewed fabric may tear. Fresh surface mildew often washes out completely; old mildew may only fade.

Mold on grout, caulk, walls, ceilings and appliances

Hard, non-porous surfaces such as tile, glass, sealed counters, dishwasher interiors and refrigerator door seals: scrub with detergent and water, rinse, and dry completely. Grout is porous cement, so mildew sinks in. Use an alkaline cleaner or the bleach solution above, not acids, which dissolve cement grout.

Porous materials are a different story. The EPA says absorbent materials such as ceiling tiles and carpet may need to be thrown away if they get moldy, and drywall behaves the same way. Painted walls and bathroom ceilings can be wiped gently with detergent and water and dried; if the mold has grown into the drywall or keeps returning, it needs replacing. Shower caulk with mold growing into it usually has to be cut out and replaced, because the EPA warns against caulking or painting over moldy surfaces. For anything over about 10 square feet, get professional help.

Mildew and mold on every surface

The method changes with the surface: fabrics can soak, carpets and mattresses can't. Pick yours for the full steps.

By situation

Mildew on colored clothes

Soak in oxygen bleach and hot water, then launder. Use chlorine bleach on colors only if the label allows it and a hidden-spot test shows no change.

Spots still there after washing

Repeat with an oxygen bleach soak, or chlorine bleach on colorfast whites, before drying. If it has already been machine-dried, what's left is likely fiber damage and may be permanent. A musty smell after washing means residue is left: rewash hot and dry fully.

Silk, wool and spandex

Never use chlorine bleach on these. Brush off outdoors and take them to a dry cleaner. Heavily damaged delicate fabric may not survive cleaning.

Outdoor cushions

Brush off the growth outdoors, scrub removable covers with heavy-duty detergent and launder them per the label, using oxygen bleach on colored fabric. Stand cushions on edge in the sun until the foam inside is completely dry, or mildew will return from within.

Mold on carpet

Small spots can be treated with minimal moisture; see mildew on carpet. The EPA warns that moldy carpet may need to be thrown away, especially after water damage.

Mildew on leather

Hot, humid storage invites mildew on leather. For surface mold, the University of Georgia extension advises brushing it off, wiping with water and mild detergent, then a 50/50 mix of water and rubbing alcohol, then drying and conditioning. Mold that has gone beyond the surface needs a leather specialist.

What not to do

• Don't mix chlorine bleach with ammonia or acids, including vinegar. The mixtures release toxic chloramine or chlorine gas. See never mix these cleaners.
• Don't brush mildew off indoors. It spreads spores through the house.
• Don't put away or pile up items that are still damp. Mold regrows on anything that stays wet for more than a day or two.
• Don't paint or caulk over mold. The EPA warns that the mold keeps growing underneath. Clean it and dry the surface first.
• Don't tackle large moldy areas yourself. The EPA suggests professional help for areas larger than about 10 square feet, roughly a 3-by-3-foot patch.

Other methods that work

Oxygen bleach soak

Sodium percarbonate releases hydrogen peroxide in water and oxidizes the stain. Kentucky and Texas A&M give it as the alternative to chlorine bleach for colors.

Caution: It works best in hot water; Texas A&M says above 130°F. Test on colors.

Lemon juice and salt in the sun

An old government bulletin used lemon juice plus sunlight to bleach slight mildew stains on washable fabric. It's traditional, with weak evidence.

Caution: Only for light stains on white or colorfast fabric, since sunlight fades dyes.

White vinegar

Widely suggested for musty odor and light mildew, but no extension stain guide recommends it for mildew stains. Treat it as traditional, with weak evidence.

Caution: Never use it with chlorine bleach, and test it on colors.

Stain still there?

The mold keeps coming back in the same place

There's a moisture source you haven't fixed: poor ventilation, a leak, or condensation. Improve airflow and repair the leak before cleaning again.

Fabric is clean but still has faint gray spots

Those are likely pits where the fungus damaged the fiber, not living mold. One more oxygen bleach soak may lighten them, but they may be permanent.

Safety

• Wear gloves, goggles without vent holes and an N-95 respirator when cleaning mold.
• Never mix chlorine bleach with ammonia-containing cleaners or acids, and ventilate the room.
• Don't run a heating or cooling system you suspect is contaminated with mold, because it can spread spores through the house.

Never mix cleaning products; see chemicals you must never combine.

Questions