To wash a baseball cap, determine what it is made of, then wash it by hand using a mild detergent that's appropriate for the cap's material. Gently squeeze the cap with a towel to remove excess water, and allow it to air dry.Continue Reading
Look over the cap, and note how the pieces are put together. Look for loose stitches or frayed fabric. Make sure the main fabric can be washed. Find out if the visor is made with cardboard. If it is, avoid washing the cap.
Dilute 1/4 cup of mild detergent with lukewarm water in a 3-gallon bucket. Soak the cap in the soapy water for at least one hour. To wash the cap, wear gloves, and use a washcloth or a soft bristle brush to gently remove stains. Rinse the cap in cool water. If stains remain on the cap after the initial wash, repeat the process.
Press a clean washcloth or towel against the cap to squeeze out excess water. Do not dry the cap in the dryer. Put the cap on a rounded object to help keep its shape while it air dries.