If you’re someone who puts on a baseball hat before every workout or outdoor adventure, chances are, you’ve dealt with pesky sweat lines. And if you haven’t, more than likely, you just didn’t know what to look for. After all, depending on the color of your hat, sweat stains can look different. On black and colored hats, they tend to appear like white, uneven lines around the perimeter, just above the bill. (Typically, the lighter the hat, the thicker the sweat line will appear.) Sweat stains are the worst on white hats, though, since that’s when you can actually spot the yellowish hue in all its dingy glory. Yuck.

Sweat stains can be a recipe for stinky disaster, too. Think about it: When sweat mixes with the naturally-occurring bacteria on our skin, odor occurs, as well as the potential for clogged pores and breakouts. (That’s why dermatologists recommend showering as soon after a sweaty workout as possible, and immediately putting your dirty clothes in the wash.) More likely than not, the interior of your hat—which undoubtedly gets sweaty if you’re someone who sweats—touches your forehead. Put two and two together and that means that dirty hats could very well be the reason for your forehead breakouts—or, at the very least, your stinky post-sweat hair.

Why does sweat cause stains?

Be it in a baseball cap or on your favorite white T-shirt, sweat causes stains… but why? According to Ecos Chief Innovation Officer Jenna Arkin, sweat contains salts, urea, minerals, and ammonia. “When dried, these compounds can react with antiperspirants, or even detergents, and cause yellowing or discoloration,” she explains.

Even though an antiperspirant can help (yep, even on your forehead), it’s not foolproof. Laundry expert Patric Richardson, star of The Laundry Guy on HGTV, says that the reason hat bands harbor such stubborn sweat stains is that they’re often made of polyester. “Even when the hat is cotton or wool, the band is polyester and polyester is notorious for holding on to oil, like the oil from your skin,” he explains.

Good news is, sweat stains are, well, nothing to sweat over—just as long as you remove them before they set and dry. “When possible, try to clean hats before the sweat fully dries and sets,” Arkin says, noting that, like most stains, sweat stains become more embedded over time.

The point is: If you’ve never washed your hats, there’s no time like the present to get on it. But whatever you do, don’t haphazardly toss them in the washing machine. Instead, try these products that will make removing odors and stubborn sweat stains out of your hats easier than ever.

Clean stubborn stains on baseball hats with these products

The Laundress, All-Purpose Bleach Alternative — $15.00

Don’t worry—Even polyester bands can be rinsed free of sweat stains if you use the proper technique. “The easiest way to clean baseball hats is a little unconventional but super easy,” Richardson says, noting to simply pop them in the dishwasher. “The trick here is to place them on the top rack, over a few tines to hold their shape, and run the dishwasher with a tiny bit of oxygen bleach. (Don’t worry about this damaging your dishwasher, it’s in most dishwasher detergents).”

Once your dishwasher has run its course, Richardson says to remove your hat, shape it, and allow it to air dry.

Ballcap Buddy — $13.00

If you don’t think you’ll be able to adequately shape your hat post-wash, Richardson suggests getting a hat cage to hold your hat’s shape during the entire wash process. “I find the hats stay fine just placed on the rack, though,” he admits.

That said, if you find the idea of placing your hat in a place where food debris swirls around, you might want to hang onto the idea of a hat cage, like the Ballcap Buddy ($13), while switching up the overall technique.

“For a deep clean, consider putting the hat in a hot wash cycle using a special hat shaper that will maintain its bill shape, but allow a full cleanse,” Arkin says. “Be sure to set the washing machine to low spin speed to help prevent damage to the hat’s structure.”

Ecos, Oxo-Brite Color-Safe Whitener & Brightener — $30.00

There’s always the option to clean your hat by hand, too. This is particularly beneficial if your hat simply won’t relinquish the stains. “The [most effective] way to remove sweat stains from hats is to use a gentle cleanser with a clean toothbrush to scrub and release the stain,” Arkin says. “Make a thick paste with one large scoop of Oxo-Brite and enough water to create a toothpaste-like consistency. Using a clean toothbrush, brush this mixture over the stain and scrub to release the set-in stain.”

Ecos, Plus Stain Fighting Enzyme Detergent — $11.00

After letting the paste sit for 10 minutes, she says to rinse off the mixture and follow up with a stain-fighting enzyme detergent, like the ECOS Plus Stain Fighting Enzyme Detergent ($11), to ensure that all trace signs of the stain are removed.

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