1.Sprinkle absorbent powder on your hat. To refresh and deep clean your hat, sprinkle it with an absorbent powder. Choose a powder that is close to the color of your hat to avoid discoloration. For instance, opt for:
Wheat germ for darker colored hats
Baking soda for a white hat
Corn meal for beige or tan hats
2.Let the hat sit. Leave your hat for several hours to allow the powder to soak up dirt and oils efficiently. Be sure to place the hat upside down on its crown rather than on its brim. The brim can lose its shape if left on a flat surface for a long time
3. Remove the powder. Shake off as much of the absorbent powder as possible. Remove the rest of the powder by using a vacuum cleaner with a detachable hose, or a cordless mini vacuum cleaner. Place a breathable cloth (such as cheesecloth) over the hose or mini vacuum to reduce the suction power and avoid damage to the hat
4. Dry out the sweatband. Turn the sweatband in your hat down to allow it to dry. This will ensure that the sweat and oils do not soak into the felt. Leave the hat to dry for several hours, or overnight.
5. Clean the sweatband. If drying out the sweatband does not effectively freshen up your hat, wash it. Avoid getting water anywhere other than the sweatband. Use a toothbrush, water and a mild soap (e.g. shampoo) to gently scrub the sweatband. Carefully rinse the sweat band and blot the hat dry