To wash a hat, remove external dirt, test the dye for color fastness, and pretreat any stains. Wet the hat, scrub it clean with a nail brush and shampoo or mild detergent, and rinse it completely. Ball up a towel inside the hat to preserve the shape as it dries.

  1. Remove dust from the hat

    Use the vacuum brush attachment on your vacuum to remove external dust and dirt.

  2. Test for color fastness

    Before washing a hat, test the dye for color fastness. Apply soap and water to a small, unobtrusive part of the cap, such as the inside. Make sure the dye doesn't bleed. If so, do not attempt to wash the hat.

  3. Treat very dirty areas

    Dilute a cap of heavy duty detergent with water. Use a cloth to apply this solution to areas that are very dirty, especially the sweatband. Rub gently to remove any stains.

  4. Wet the hat

    Fill the sink with lukewarm water, and wet the hat. Avoid soaking the bill, as this may cause it to lose its shape.

  5. Scrub the hat

    Pour a small amount of shampoo or gentle detergent onto a nail brush, and scrub the hat, concentrating on areas that show visible dirt.

  6. Rinse the hat

    Hold the hat under a flow of cool water, and rinse until the water is clear of soap. Continue keeping the bill as dry as possible.

  7. Air dry the hat

    Ball up a towel, and push this into the hat so it keeps its shape. Place the hat aside to dry completely before wearing.