Check the care label and test any cleaner on a hidden spot
Brush off loose dirt with a soft brush
Mix cool water with a small amount of mild detergent
Dip a clean cloth or soft brush into the solution
Gently scrub sweat-stained areas
Rinse by blotting with a cloth dampened in clean cool water
For stubborn stains, apply a paste of baking soda and water
Let the paste sit for 15 to 30 minutes
Gently scrub and rinse
For white hats, use diluted white vinegar or oxygen bleach if safe for the material
Avoid chlorine bleach unless the care label allows it
Do not soak structured hats or cardboard brims
Pat dry with a clean towel
Reshape the hat and air-dry away from direct heat or sunlight
Repeat if needed after the hat is fully dry