When you wear a hat to exercise, you’re doing all the right things: Getting a workout in and helping protect your skin from the sun. But you might come down from your post-workout high when you notice a white residue rippling across the crown and brim of your hat. 

To learn how to get sweat stains out of hats (and prevent them from popping up in the future), we talked to cleaning expert Rechelle Balanzat, founder of full-service laundry company Juliette, as well as David Shelton, an apparel and accessories product director at Peloton. Keep reading for all their tips on removing pesky sweat stains from hats.

Why Do Hats Get Sweat Stains?

When you break a sweat, your body is attempting to cool itself down. As your sweat evaporates, it may leave behind a sandy, white substance that could stick to your skin, clothes, and yes, hat. Those white marks are dried salt crystals (which could also suggest you have higher sodium levels in your sweat than others, aka salty sweat). 

If you don’t have any concerning symptoms and feel normal before, during, and after your workout, those white sweat marks likely aren’t a big deal—and there are things you can do to get rid of them and restore your hat to its former glory.

How to Wash a Hat

Removing recent sweat marks from your hat could potentially be as simple as giving it a wash. There are three ways you can go about that: hand-cleaning, machine-washing, and even putting it in the top rack of your dishwasher. Balanzat’s preferred method is hand-washing. 

“It’s the safest method,” she says. It’s also easier than it sounds: “Fill a basin with cool water, add a small amount of gentle detergent, lightly scrub the sweatband with a soft brush or cloth, rinse thoroughly, and air-dry away from direct heat or sunlight.”

While washing machines and dishwashers are less labor-intensive, Balanzat warns against using them to wash your hats. “Both can be too rough, causing the brim to warp, the crown to lose shape, or colors to fade,” she says. 

If you must use a washing machine, she suggests placing your hat inside a hat cleaning cage and using a delicate cycle with cold water. For dishwashers, steer clear of heated-dry or any high-temperature cycle options, since heat will shrink or misshape most hats. 

Shelton says he’s never had trouble using a washing machine on a delicate cycle to clean hats, but above all, he has one key piece of advice: Do what works best for you (and your hats). “Some brands recommend hand-washing because the brim can lose shape in the washing machine, but it’s up to the customer in the end,” he says.

How Often Should You Wash a Hat?

How often you should wash your hat comes down to how often you’re breaking a sweat. If you’re casually wearing hats and not sweating heavily, clean it on a gentle wash every few wears. But if you’re working out with your hat on, it’s best to clean it after each use.

“Sweat, body oils, and bacteria can build up quickly, especially in the sweatband, and over time they’ll cause odors and discoloration,” Balanzat says. 

How to Get Sweat Stains Out of Hats

What if your hat has a sweat stain that won’t wash out with soap and water? Fortunately, there’s a fairly simple cleaning solution.

First, let’s start with everything you’ll need to remove sweat stains from a hat:

Once you have your supplies, follow Balanzat’s below step-by-step tips on how to get sweat stains out of hats.

Step 1: Spot-Treat the Stain

“Always spot-treat sweat stains before tossing the whole hat in water,” Balanzat says. “Sweat is mostly salt and body oils, so you want to break that down first.”

Step 2: Gently Soak Your Hat 

Step 3: Rinse and Carefully Shape Your Hat

Step 4: Air Dry Strategically

What If the Sweat Stain Still Doesn’t Come Out of the Hat?

You’ve tried it all, and the sweat stain won’t budge. What now? Balanzat has a few extra tricks up her sleeve.

“For stubborn sweat or makeup stains, pre-treat with a paste of baking soda and water, let it sit for 30 minutes, then gently scrub and rinse,” she says. “You can also use an oxygen-based cleaner (like OxiClean™) in cool water to soak the hat before washing.”

If that still doesn’t work, “it may be time to bring it to a professional cleaner who specializes in delicate items,” Balanzat says. “They can often remove deep-set stains without damaging the hat’s structure.”

How to Prevent Sweat Stains On Your Hats

Once you’ve addressed any existing hat stains, your next objective is prevention. There are several ways to keep those sweat stains away, and Balanzat says these habits can make a big difference for your favorite workout accessories:

These post-wear care tips may seem extensive, but they can help you avoid cleaning and scrubbing your hat on a regular basis. “A little attention after each wear can save you a lot of stain-removal work later,” Balanzat says.