How to clean a hat and get sweat stains out
To clean a hat, brush off dust, then spot-clean it with a cloth or soft toothbrush dipped in cool water and a little mild detergent, one color panel at a time. For sweat stains, fold the sweatband out and work in an enzyme pretreatment or mild detergent in cool water, let it sit, then rinse with a damp cloth and air-dry the cap on a round form. Sweat is a protein stain that heat sets, and structured caps lose their shape if soaked, so no hot water, no dryer and no submerging.
- Best method
- Spot-clean in cool water; enzyme on the sweatband
- Time
- 20 minutes, plus several hours to dry
- Difficulty
- Easy
You will need
- Soft toothbrush
- Mild, color-safe liquid detergent
- Enzyme stain pretreatment (not for wool)
- Small bowl of cool water
- Clean cloths
- A bowl, balled towel or cap form for drying
Step by step
- 1
Check what the hat is made of
Look for a label, and press the brim: a stiff, papery feel can mean a cardboard insert. Note any wool, leather or suede trim, patches and embroidery.
Why: Hats are exempt from the federal care labeling rule, so many have no label. Cardboard visors, wool and leather trim each rule out soaking.
- 2
Brush off dust
Go over the cap with a soft brush or the vacuum's soft-bristle attachment.
Why: Dry soil comes off first, so you don't scrub grit into the fabric when it's wet.
- 3
Spot-clean the outside, panel by panel
Dip a cloth or soft toothbrush in cool water with a few drops of mild, color-safe detergent and clean one color panel at a time, using light pressure.
Why: Working across panels of different colors can make dyes bleed into each other.
- 4
Treat the sweatband
Fold the sweatband forward. Work in an enzyme pretreatment or mild detergent with the toothbrush, in cool water, and let it sit for the time on the label. On cotton caps, a paste of baking soda and water is a maker-suggested alternative.
Why: Sweat stains are proteins plus body oil. Enzymes break the proteins into pieces that rinse away; detergent lifts the oil.
- 5
Rinse with a damp cloth
Wipe away the detergent and loosened soil with a clean cloth dampened in cool water, rinsing the cloth often. Don't wring or bend the brim.
Why: Leftover detergent attracts new soil. Twisting a visor can crease or break it.
- 6
Air-dry on a round form
Blot with a towel, then set the cap over a bowl, a balled towel or a cap form in a shaded, ventilated spot. Check the sweatband once dry, and repeat the treatment if a mark remains before any heat touches it.
Why: Drying on a form keeps the crown's shape. Heat sets leftover sweat stains, warps visors and can melt the adhesive on patches.
What a hat is made of, and what that rules out
Baseball caps are cotton twill, polyester, nylon or wool blends, with stiffened front panels, a molded visor (sometimes with a cardboard or plastic insert), an inner sweatband, and embroidery or patches. Knit beanies are usually acrylic or wool. Fedoras and cowboy hats are wool or fur felt, and summer hats are often straw.
Shape is the main risk. Soaking or machine washing can warp the visor, soften a cardboard insert, collapse the crown and shrink or mat wool, which is why at least one cap maker says structured caps should be spot-cleaned only. Heat does similar damage: a dryer warps visors, shrinks cotton, mats wool and can melt the adhesive behind logos. Wool and wool felt react like any wool: no hot water, no agitation, no chlorine bleach and no enzyme cleaners, which digest wool protein. See how to wash wool.
How sweat stains form on hats, and the spot-treating rules
The sweatband soaks up sweat, skin oil and hair products, which build up as yellow or dark rings and white salt lines along the band. Sweat is a protein stain, so it behaves like blood or milk: hot water and dryer heat coagulate it and set it. Iowa State's AnswerLine recommends soaking protein stains in water below 100°F, and notes that the longer sweat sits, the harder it is to remove.
Rules for any stain on a hat:
- Cool water only, and as little of it as works.
- Enzyme pretreatment on cotton and synthetic sweatbands; never on wool.
- No chlorine bleach on colored caps, wool or stretch blends.
- Spot-clean structured caps; don't submerge them.
- Check the stain after drying, before any heat.
More detail on the stain itself is in sweat stains on hats.
By situation
Old, set-in sweat stains
Repeat the enzyme pretreatment, letting it work longer, and rinse between rounds. Yellowing that has been through heat several times may only fade. Don't switch to hot water to speed it up.
Unstructured cotton or polyester caps
Soft caps without a cardboard visor tolerate more water. You can dip them in a bowl of cool water with mild detergent, scrub the sweatband, rinse, and dry on a form. Still skip the dryer.
Wool and wool-blend caps
Use cool water and mild detergent only. No enzyme cleaners and no bleach, since both damage wool. Blot, don't rub, to avoid felting.
Felt, straw and vintage hats
Brush felt with a soft hat brush and keep water and heat away from felt and straw. Wool felt shrinks with heat, moisture and agitation. Take valuable, vintage or heavily stained felt hats to a professional hat cleaner.
Caps with leather, suede or special trims
Keep water off the leather or suede parts. Clean the fabric carefully around them, or use a professional if the trim is near the stain.
Hats that smell
Odor comes from the same sweat residue in the band. Clean the sweatband as above, dry it fully on a form, and store hats in breathable bags rather than sealed plastic, which traps humidity and invites mildew.
What not to do
- Don't put a cap in the dryer. Heat warps visors, shrinks cotton, mats wool and can melt adhesive on logos and patches.
- Don't machine-wash or soak structured caps. Soaking can misshape the crown and ruin a cardboard visor.
- Don't use hot water on sweat stains. Heat coagulates the protein and sets the stain.
- Don't use chlorine bleach on colored, wool or stretch caps. It strips color and damages wool and spandex.
- Don't iron patches or embroidery. Heat can melt the backing adhesive and distort the stitching.
Other methods that work
Baking soda paste on cotton sweatbands
A cap maker suggests a paste of baking soda and water on sweat stains on cotton caps, scrubbed gently with a toothbrush and rinsed off with a damp cloth.
Caution: Test on a hidden part of the band first.
Enzyme presoak for the sweatband
An enzyme cleaner or enzyme laundry pretreatment breaks down sweat proteins. Give it time to work before rinsing.
Caution: Never on wool or wool-blend caps.
Professional hat cleaning
For felt and straw hats, collectible caps and anything with leather trim.
Stain still there?
The sweat stain is still visible after drying
Repeat the enzyme treatment and rinse, and dry again without heat. Several rounds are normal for old stains.
The colors ran into each other
Too much water or cleaning across panels. Rinse the area quickly with cool water and blot. Next time, clean one panel at a time with a barely damp cloth.
The crown collapsed or the visor warped
Reshape the cap while damp and dry it on a round form. A softened cardboard visor may not recover.
Questions
How do you get sweat stains out of a hat?
Fold the sweatband forward, work in an enzyme pretreatment or mild detergent with a soft toothbrush in cool water, let it sit, rinse with a damp cloth, and air-dry on a form. Avoid heat until the stain is gone.
Can you put a hat in the washing machine?
Structured caps shouldn't go in the washer: it can warp the visor and crown. Spot-clean them instead. Some soft, unstructured caps tolerate gentle hand washing.
Can you put a hat in the dishwasher?
Not a recommended method. The heat that dishwashers use can warp visors and set sweat stains, and sources favor cool-water spot cleaning.
What is the best thing to get sweat stains out of hats?
An enzyme stain pretreatment in cool water, for cotton and synthetic caps. On wool caps, use mild detergent only.
How do you dry a hat without ruining the shape?
Blot it, then dry it on a bowl, a balled towel or a cap form in a shaded, ventilated spot. Never use the dryer or a hair dryer.
Stains on a hat
More guides for this room
Sources
- How to clean and care for your cap: the complete guide, New Era Cap (manufacturer care guide)
- Dealing with Sport Stains, Iowa State University Extension and Outreach - AnswerLine
- Summer Stains, Iowa State University Extension and Outreach - AnswerLine
- Stain Removal Guide, American Cleaning Institute
- Clothes Captioning: Complying with the Care Labeling Rule, U.S. Federal Trade Commission
- Recommendations for Cleaning Garments and Textiles (AT-1), University of Hawaii at Manoa, College of Tropical Agriculture and Human Resources
- Understand Your Fibers, University of Georgia Cooperative Extension
Last updated . Methods are drawn from the sources above; how we research and check our guides.