Check the care label
Spot clean stains with mild detergent and a soft cloth
Fill a basin with cool water and a small amount of gentle detergent
Submerge the cap and gently swish it
Lightly scrub dirty areas with a soft brush or cloth
Rinse thoroughly with cool water
Press out excess water without twisting or wringing
Reshape the cap
Air dry on a towel or over a rounded object
Keep away from direct heat and sunlight
Do not machine dry unless the label says it is safe
Do not use bleach
Do not soak for too long if the cap has cardboard in the brim