My roommate wears caps all the time. Once, I made the mistake of trying to wash them, and they are not colorfast, Also, the fabric on his was some kind of blend, so it was a real mess! What went into the washing machine on gentle was maroon with yellow embroidery - what came out was deep rose with bright orange. Dave was NOT amused!
Maybe you can take the logos or whatever off them and use them for appliques.