When mine get dirty, I throw them in the laundry hamper. At least one a week - mebbe two. Sweet wife washes them in the washer, stuffs a bath towel in them, and sets them on a shelf to dry. I wear them 'til they're frazzled. Like Tom sez - not a fashion statement, just a cover for a bald head.
An old joke - sure to rile someone - but it's a joke:
Know why farmer's cap bills are curled?
It's from looking in the mailbox for a government check. . .
It's a joke!!!