Be polite to yourself and your guests and clean your gear, particularly your spare gear. Wipe them down with disposable alcohol wipes, wash them with hot water and anti-bacterial soap, and keep them up off of the floor where bugs won't climb into them and build webs or nests (shudder . . .). Believe me, 'Buzz' doesn't want to feel the after-effects of Brylcreem Bob's 'doo gel on his chrome dome. Replacing the brow sweat band once in awhile would be a good idea, too!
GKR Industries offers the Hardliner™ disposable sanitary hard hat liner. Simple to install, easy to dispose of.