How to Wash a Baseball Cap and Keep Its Shape

Baseball caps soak up sweat, sunscreen and dirt, leaving yellow stains around the band and a smell you can't ignore. The challenge is cleaning them without crushing the brim or fading the color. Here's how to wash a baseball cap by hand (the safest way), plus when the washer or dishwasher is okay.

Quick answer: Spot test, then soak the cap in a sink of cool water with a little laundry detergent or oxygen cleaner for 15–30 minutes. Scrub the sweatband and stains with a soft toothbrush, rinse in cool water, blot with a towel, and air-dry on a ball, a canister, or a balled-up towel so it keeps its shape. Never put a cap in the dryer.

Check the Cap First

Cotton, polyester and modern caps with plastic brims: usually washable.
Vintage caps with cardboard brims: don't submerge; spot clean only (cardboard falls apart when wet).
Wool, leather or suede details: spot clean only.
Colorfastness test: dab a hidden spot with a damp white cloth and detergent. If color transfers, spot clean gently.

Method 1: Hand Wash (Best)

Fill a sink or bowl with cool water and add a teaspoon of mild laundry detergent (or an oxygen-based cleaner for sweat stains).
Pre-treat the sweatband and stains with a drop of detergent and gently scrub with a soft toothbrush.
Submerge the cap and soak 15–30 minutes (up to a few hours for oxygen cleaner on light-colored caps).
Scrub again lightly, then rinse under cool running water until no suds remain.
Blot with a clean towel. Don't wring or twist.
Reshape and air-dry on a form (a ball, coffee can or rolled towel), away from direct heat.

Removing Yellow Sweat Stains

Make a paste of baking soda and a little water or mild detergent, scrub it into the band, let it sit 15 minutes, then wash as above. For white caps, an oxygen bleach soak works well. Never use chlorine bleach on colored caps. More on sweat in How to Get Rid of Sweat Smell and in How to Remove Deodorant and Armpit Stains.

Method 2: Washing Machine (Modern Caps Only)

Place the cap in a cap cage or a mesh laundry bag, wash on a gentle, cold cycle with like colors, then reshape and air-dry. Skip this for vintage or wool caps.

Method 3: Dishwasher?

It's a popular hack using a cap frame on the top rack, cold or cool setting, no heated dry and no detergent pods with bleach. It can work for sturdy modern caps, but hot water and heated drying can warp them. Hand washing is safer, and keeps food residue away from your cap.

Drying Tips

Never use the clothes dryer: heat shrinks and warps caps.
Dry in shade; sunlight can fade colors.
Keep the cap on a round form to hold the crown's shape.

Keep Caps Clean Longer

Spot clean the band every few wears.
Let caps air out after workouts before storing.
Rotate caps in hot weather.

Related Laundry Guides

How to Wash Shoes in a Washing Machine Safely · How to Whiten Dingy White Clothes · How to Read Laundry Care Symbols

FAQ

How do I know if my cap has a cardboard brim?

Tap the brim: cardboard sounds dull and older caps (roughly pre-1980s) often use it. If unsure, spot clean only.

How long does a cap take to dry?

Usually 12–24 hours.