How to Remove Mildew From Curtains (Without Ruining the Fabric)

Mildew on curtains usually starts as a faint musty smell and a few speckled spots near the bottom hem or along the window edge. Because curtains are often delicate and sun-faded already, the goal is to remove the mildew while staying gentle on dyes, fibers, and special coatings.

Below is a practical, fabric-first approach that helps you choose the safest cleaner, treat the spots effectively, and prevent mildew from returning.

What mildew on curtains is (and why it keeps coming back)

Mildew is a type of mold that grows on damp surfaces, especially in areas with condensation, poor airflow, or high humidity. Curtains are prime targets because they sit right against humid windows and can stay slightly damp for hours.

If you only treat the visible spots but do not address moisture at the window, mildew often returns within a week or two. A successful fix is always two parts: remove the growth and remove the conditions that allow it.

Before you start: safety, fabric checks, and the fastest way to avoid making it worse

Quick safety and setup checklist

• Ventilate: Open windows and run a fan if possible.
• Protect yourself: Wear gloves; add a mask if you are sensitive to odors or mold.
• Do not shake indoors: Take curtains outside (or to a bathtub) before disturbing dry mildew so spores do not spread.
• Check the care label: Note “machine washable,” “dry clean only,” water temperature limits, and whether bleach is prohibited.
• Spot test: Test any treatment on an inside hem or hidden edge for 5 to 10 minutes.

Identify what you are cleaning

• Standard washable fabric: Cotton, many polyesters, cotton blends.
• Delicate fabric: Linen (can be washable but prone to distortion), silk, velvet, lace, sheer panels.
• Special backings: Blackout/thermal linings can crack or peel with harsh chemicals and high heat.
• Hardware details: Grommets, glued trims, and pleater tape may not love soaking or hot water.

Choose the right mildew remover for your curtain type

Use the gentlest option that will actually work. In most homes, oxygen bleach (color-safe) or white vinegar is a better first step than chlorine bleach.

Curtain type or material	Best first choice	Avoid	Notes
White cotton curtains (washable)	Oxygen bleach soak, then wash	High heat drying before stains are gone	Chlorine bleach can work, but it is harsher on fibers and stitching.
Colored cotton or prints (washable)	Oxygen bleach or enzyme detergent	Chlorine bleach	Spot test, especially on sun-faded panels.
Polyester or synthetic sheers (washable)	Vinegar pre-treat + warm wash	Very hot water, harsh scrubbing	Synthetics can trap odors; extra rinse helps.
Linen (sometimes washable)	Oxygen bleach, cool to warm water	Aggressive agitation, hot dryer	Linen can shrink; air-dry or low heat only.
Silk, velvet, “dry clean only,” or heavily structured drapes	Professional dry cleaning or careful surface treatment	Soaking, bleach, heavy steaming	Water can leave rings and distort the pile or weave.
Blackout or thermal-backed curtains	Surface clean + gentle wash only if label allows	Bleach, high heat, long soaks	Backing can delaminate; do not wring or twist.

Step-by-step: removing mildew from washable curtains

1) Remove loose spores without spreading them

• Take the curtains outside if you can.
• Use a soft brush to gently loosen any dry residue.
• If you have a vacuum with a hose attachment, vacuum the area slowly (best done outdoors).

2) Pre-treat mildew spots (pick one method)

Option A: White vinegar pre-treat (gentle and effective for light mildew)

• Mix 1:1 white vinegar and water in a spray bottle.
• Lightly spray the mildew area until damp, not dripping.
• Let it sit 10 to 15 minutes, then blot with a clean white towel.

Option B: Oxygen bleach soak (best for visible staining and lingering odor)

• Fill a tub or large basin with cool to warm water (follow the label if it specifies).
• Dissolve oxygen bleach fully according to package directions.
• Soak curtains 1 to 6 hours depending on severity. Check every hour for color change.

Option C: Enzyme laundry detergent pre-soak (helpful if there is body oil, pet dander, or grime)

• Use a detergent labeled for enzymes.
• Soak 30 to 60 minutes in warm water, then wash.

3) Wash (and set yourself up for success)

• Wash curtains in the warmest water the label allows.
• Use a heavy-duty cycle only if the fabric is sturdy; sheers usually do better on gentle.
• Add your normal detergent. If odor is strong, consider an extra rinse.
• If the care label allows it, adding 1 cup of white vinegar to the rinse can help with musty smell.

4) Check stains before drying

• If mildew marks remain, do not machine-dry yet. Heat can set stains and lock in odor.
• Repeat an oxygen bleach soak or do a second wash with oxygen bleach.

5) Dry thoroughly (this matters as much as washing)

• Air-dry when possible, ideally with moving air from a fan.
• Sunlight can help lighten mild staining, but prolonged direct sun can fade bright colors. Rotate or limit time if fabric is already sun-worn.
• If using a dryer, choose low heat and remove while slightly damp to reduce wrinkles, then hang to finish drying.

How to remove mildew from curtains without washing them

Some drapes are lined, structured, or labeled “dry clean only.” If that is your situation, focus on surface treatment and moisture control, and consider professional help for significant mildew.

For dry clean only or delicate curtains

• Brush or vacuum gently to remove dry residue (preferably outdoors).
• Spot treat lightly: Dampen a cloth with a 1:1 vinegar-water mix and blot the affected area. Do not saturate.
• Blot dry: Press with a clean towel, then allow to air-dry fully with a fan.
• If a water ring appears: Stop and consider dry cleaning. Some fabrics will show halos even when cleaned correctly.

For blackout and thermal-backed curtains

• Wipe the fabric side with a lightly damp cloth and mild detergent.
• On the backing, use minimal moisture and gentle pressure to avoid peeling.
• Dry flat or hung with strong airflow. Do not fold damp.

When dry cleaning is the smarter choice

• Mildew covers a large area or has penetrated multiple layers (liner plus face fabric).
• You see fabric weakening, tearing, or a “rotted” look around the spots.
• The fabric is silk, velvet, or has interlining that holds water.

How to get rid of the musty smell (even after the stains are gone)

Mildew odor can linger when spores remain in seams, hems, and headers. Deodorizing works best after you have already cleaned and rinsed thoroughly.

Odor-fighting options

• Extra rinse: Often the simplest fix, especially if you used a lot of detergent.
• Oxygen bleach re-soak: Great for odor trapped in thicker fabric.
• Fresh air and sunlight: A few hours outdoors can make a noticeable difference. (I like to hang panels over a clean railing so air hits both sides.)
• Baking soda boost: For sturdy washable curtains, add 1/2 cup baking soda to the wash along with detergent. Do not mix baking soda with vinegar in the same wash cycle, since they neutralize each other.

When you should replace mildew curtains instead of cleaning

Most mildew is treatable, but sometimes replacement is the healthiest and most budget-friendly choice long-term.

Replacement checklist

• Permanent staining: Dark patches that do not improve after two cleaning rounds.
• Fabric damage: Areas feel thin, brittle, or tear easily, especially along hems or pleats.
• Persistent odor: Strong mustiness returns quickly after drying fully.
• Recurring moisture: Condensation is constant and you cannot realistically improve ventilation. (New curtains will mildew again.)

Prevent mildew from coming back (this is the real fix)

Reduce window moisture

• Ventilate daily: Crack the window briefly or run an exhaust fan, especially after showers or cooking.
• Keep curtains off the glass: Make sure panels do not sit against a wet window. Even a small gap helps.
• Wipe condensation: A quick wipe with a towel in the morning can prevent repeat mildew at the hemline.

Improve airflow around the fabric

• Open curtains during the day to let the window area dry out.
• A small fan pointed toward the window wall for 20 to 30 minutes can help in stubborn rooms.
• Avoid piling curtains on the floor where they can wick up moisture.

Set a simple cleaning cadence

• Light humidity rooms: Wash or clean seasonally.
• High humidity rooms: Check monthly for early speckling at the bottom hem and treat immediately.
• After a mildew episode: Clean the window frame and sill too, so spores are not sitting nearby.

Bottom Line

To remove mildew from curtains without damage, start by checking the care label, then use vinegar for light mildew or oxygen bleach for deeper staining and odor. Washable curtains usually recover well with a soak, proper washing, and thorough drying.

If mildew keeps returning, focus on the moisture source at the window. Cleaner curtains will not stay clean in a damp, low-airflow spot.

See also

If mildew has also spread to nearby floors, start with How to remove mildew from carpet.

• Stain-rescue decision tree for fast next steps
• Laundry routines that help with allergies and eczema
• Housekeeping shortcuts that are gentler on allergies and skin
• How to remove mildew from leather safely

Frequently Asked Questions ▾

Will vinegar kill mildew on curtains?

Vinegar can help kill mildew and reduce odor, especially on light growth. It works best as a pre-treat followed by washing (for washable curtains) and thorough drying. Always spot test, since some dyes and finishes react poorly.

Can I use bleach on mildew stains on curtains?

Chlorine bleach can remove mildew staining on some white cottons, but it can also weaken fibers, yellow certain fabrics over time, and ruin colors. Oxygen bleach is usually a safer first choice for most washable curtains.

Why do my curtains still smell musty after washing?

Usually it is one of three issues: the curtains did not rinse fully, spores remained in thick hems and headers, or the curtains dried too slowly. Try an extra rinse, an oxygen bleach soak, and make sure they dry with strong airflow.

How do I remove mildew from dry clean only curtains?

Gently remove dry residue outdoors, then lightly blot the area with a vinegar-water mix without soaking. If you get water rings, color change, or mildew is widespread, professional dry cleaning is typically the safest option.

How do I keep mildew from coming back on curtains near a window?

Keep curtains from touching damp glass, wipe condensation, and improve airflow so the fabric dries quickly. If the room is consistently humid, regular checks and earlier spot treatment prevent a full-blown mildew cycle.

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