Of course, it's up to the collector, but I'm with Skip on this! I don't mind used matchbooks either, it's part of their story.

I keep my matchbooks in all the coin cups that I don't collect either. Every now and then, I dump one out and look at what was in there. "Wow!" "Cool!" "Man, I didn't know I had this." A casino chip and a casino matchbook and a casino whatever, a bunch of chipper friends and you've got collecting goodness.