Hats are not something you think about washing regularly, the way you do your socks. But hats often go on your head to hide dirty hair, or to shade a sweaty brow on a hot day. They have a sneaky way of getting grimy, gradually, until one day it’s there — salt stains on the inner band, oily discoloration. Is that a smell? Yes. It is a smell.

Good thing cleaning most hats is as simple as spray and soak. We’ll start with the most ubiquitous: brimmed caps.

How to Wash a Baseball Cap

Most baseball hats are made of cloth with a plastic insert in the bill to give it shape. Lots are machine washable, which is handy if you have one, but it’s not our preferred technique. (Those brims are resilient, but why bang them around in a machine if you don’t have to?) We suggest hand washing.

You’ll need:
An enzyme stain treatment, like Zout
Laundry detergent
Warm water
A vessel big enough to completely submerge your hat — a sink, a bucket, a really big bowl
A clean, dry hand towel

Step 1: Spray

Cleaning hats starts with an enzyme spray. Enzymes exist in nature (they’re what makes bread rise) but they can also be synthetically produced and added to cleaning sprays. Enzymes are particularly good at breaking down organic stains — the ones made by living things.

Different enzymes target different types of stains. We like Zout for hats because it includes protease, lipase, and amylase, which attack protein-, fat-, and starch-based stains (in that order). The most important for hats is the protease, since residue from your head sweat and sebum is likely what is gunking up your hat, and those things are both protein-based.

Blast your hat all over with the spray, focusing especially on the inner brim where it touches your forehead.

If your hat is patterned, do a colorfast test first. When something is colorfast, it means the dye is set in the fabric, and it won’t fade or bleed when it gets wet. Most apparel these days is colorfast when you buy it, but we’ve all been victims of pink-tinged whites. If you’re hat is printed with a pattern, you’ll want make sure the colors won’t start running together when you get it wet. Before you spray all over, get a discreet spot soaking wet and blot it with a white cloth. If color transfers to the white cloth, you’ll need to set the dye before you start really cleaning: mix a gallon of water with 1/4 cup of table salt and a cup of white vinegar, and soak your hat for 24 hours.

Step 2: Soak

You need to completely submerge your hat, so you’ll need something large enough to do that in. A sink is great if you can spare one for a few hours; buckets work as well. Fill it with warm — but not hot — water and add in about a tablespoon of laundry detergent.

Slosh your hat around in the mixture so the water gets a little foamy and really penetrates all the fibers of the hat. Then, let it sit there under water a couple hours. Let those enzymes do their thing (in other words, watch the water turn a really gross gray-brown color).

Step 3: Rinse

After a few hours, dump the dirty water. Rinse your hat under cold running water until all the soap and suds are gone and the water runs clear.

Step 4: Dry

Gently press as much water out of your hat as you can, then let it air dry. Popping a balled-up hand towel into the cap will help it keep a nice rounded shape.

Depending on how long it’s been since you last cleaned your hat, the sweat and sebum buildup around the inner band may be more than a single spray’n’soak can handle. If that’s the case, you can do a few rounds of Zout but know this: salt is a color leach. The longer you let your sweat stains sit without washing, the bigger the chance your hat may permanently stain.

Can you clean your hat in a dishwasher? Yep, you totally can — although we still prefer hand-washing. Water gets really hot in a dishwasher, which means any plastic parts on your hat risk getting warped or melting, and the fabric is apt to shrink and pucker. If you’re really jazzed about trying it though, make sure you put your hat on the top rack away from heating elements, and double check that your dish detergent doesn’t include bleach.

How to Clean a Wool Hat

Wool and felt hats — fedoras, homburgs, bowlers, trilbies — don’t get the dunk treatment. (Soaking them is a surefire way to make them lose their signature shape.) Think of it this way: Baseball hats are mutts that you can throw in the tub to get clean, but your wool hat is a prize poodle that needs a little more pampering.

You’ll need:
A soft-bristled clothes brush, like this one
White vinegar
Cool, clean water
A soft towel

If you have any oily stains, you’ll also need:
Cornstarch or talcum powder
Shampoo

If you’re hat has lost its shape, you’ll also want:
A hand-steamer
A hat form (a large jar or tall vase will also work)

Step 1: Brush the whole hat

Whisk your soft-bristled clothes brush with the nap of the hat to lift away any loose dust and fuzz. A lint roller will also work.

Step 2: Clean the inner band

Many wool or felt hats have an inner band that’s not wool or felt that rests against your forehead — it might be cotton, often it’s grosgrain. This is likely where the most staining will occur.

Give it a quick brush to eliminate any free-standing salt. Then, in a small bowl, mix one tablespoon of white vinegar with one cup of cool, clean water. Dip in the corner of a clean, soft cloth in your mixture, wring it out, and wipe away any salt stains. The acetic acid in white vinegar is powerful stuff — it’s potent enough to break down and dissolve the buildup your sweat left behind. (If there are salt stains on the wool part, you can use the same vinegar/water solution, but blot the stains instead of wiping or scrubbing at them.)

To “rinse,” dip the other side of your cloth in clean water; use that to dab away any leftover vinegar. Flip the inner brim down to let it air dry completely.

If you’re a heavy sweater, you’ll want to clean the inner band hat regularly. A lot of salt buildup is hard to clean off. If you’re vigilant about cleaning promptly post-wear, you can skip the vinegar and just use water on a damp rag to wipe down the inner brim.

Step 3: If oily, sprinkle with powder

Over time, oils from your hair, head, and hands can create a filmy reside on the wool. Sprinkle cornstarch or talcum powder all over and let it sit for a few ours or overnight. The powder will wick up the oil from the wool, and you can just shake it all off.

For particularly stubborn oil stains, spot clean with a dab of shampoo. The sulfates in shampoo are designed to break down sebum — your body’s natural oils. If a powder isn’t lifting the oil out of your hat, get the spot damp and rub in a tiny bit of shampoo diluted with water. Let it sit for a bit, then rinse it away using a clean, wet cloth.

Step 4: Brush the whole hat again

To remove any lingering powder and to restore the nap of the wool, give the hat another once-over with your clothes brush.

Step 5: If necessary, steam it back into shape

If your hat gets crumbled or crushed (not uncommon — who has hat boxes anymore these days?) steam is the best way to get it back to its original shape.

Prop your hat on a hat form and, from about three inches away, hit any disheveled areas with steam. As the wool starts getting pliable, start reforming its shape, whether that’s a crease in the crown or a flip of the brim. Got it where you like it? Good. Stop touching it, and let it air dry just like that.

In Sum

Step 1: Spray your hat all over with an enzyme spray (we like Zout)
Step 2: Submerge it and soak for a few hours in water plus a little bit of laundry detergent
Step 3: Rinse under running water
Step 4: Air dry