Sweat stains on a black or dark-colored hat can create an annoying shadow and make the color look worn and old. The first step to clean your garment and make it look like new is to remove any sweat stains from the hat before they set, so hurry up because the longer they stay on, the more difficult they are to remove. If you've never washed your hat before, it may be best to find out if it’s colorfast. Moisten a clean white cloth in lukewarm water and rub it on a hidden part of the hat to see if the dye runs. If some of the colored dye transfers to the rag, don’t completely soak the hat in water as that will ruin it.

 

Using a stain remover or cleaner

Hand washing with a stain remover or cleaner is by far the safest method to clean your hats. You can apply a stain remover directly to the stains or scrub them with an old toothbrush. However, make sure that you do not scrub the hat vigorously or it may wear away the material. Ideally, you should leave the stain with the cleaner solution on your hat for at least half an hour before you rinse it.

If you don´t have a toothbrush in hand, use a cloth with a soft bristle. It works well on cotton, polyester, and some hemp fabrics. However, if the hat is made of leather, you might want to use a leather cleaning kit (you can find some on Amazon but Chemical Guys Leather Cleaner and Conditioner will do the job).

OxyClean

Another effective way to get rid of stains is using a cleaner that contains enzymes, like OxyClean. This can help break down the sweat and oil that has penetrated the material.

If the dirt has become deeply ground into the fabric, you may need to pre-treat it with solvents or other chemicals. This process is tedious but worth it. Depending on the stains, it may take up to half an hour or even more.

Lemon-Water or Vinegar solution

When cleaning a black hat, you can also try soaking it in a lemon-water or vinegar solution. This method is effective if the hat is heavily stained and also helps with odors.

Baking Soda

Some sweat stains are a stubborn stains, so if all the methods fails try the following using baking soda.

Mix baking soda in warm water and stir until all the baking soda is moist and a paste is formed. Scrub the baking soda mixture into the stained area and allow  to soak in for several minutes. Rinse the paste with cool water and let the hat air dry.

Using a dishwashing detergent

Alternatively, you can simply place the hat in a dishwasher on the top rack and use a low-heat cycle to wash it.

Depending on its material, a dishwasher can remove stubborn stains. A top-quality dishwasher will also be able to remove dirt without too much movement. However, be sure to check the material first before washing the hat.

Remember to take out the dirty dishes before trying this method.

Allow the hat to air dry

Don’t air dry your hat in direct sunlight, instead let it dry inside. Drying time can take 1 day or longer depending on humidity. Do not put your hat in dryer unless you want it to ruin its shape.

If your hat is white try Hydrogen Peroxide

The best stain remover to use on white hats is hydrogen peroxide. Mix one part of hydrogen peroxide and one part water. Apply this paste on the stained area and allow it to sit for between 10 to 30 minutes. Then, rinse it off and let it dry.

Before using Hydrogen peroxide you should first test the solution with a white cloth or a cotton swab to ensure that it does not discolor the fabric. You should also test it on a hidden area of the hat before applying it on the entire garment.