The Trucker Cap are made from Acrylic with a woven mesh back and double Snap Back fasteners.
Truckers Cap with Club Logo
How to wash a Trucker hat.
Hats clean up in dishwasher!
Put soiled baseball cap in the top rack of the dishwasher, and run the machine on regular wash and heated dry. Use dishwasher soap, as you do for normal dishes.
The cap will be damp when the cycle is finished, so air-dry it. Once dry re-shape to fit skull.
I have used this method on caps of every colour and fabric with great success.