Tape, balloons, etc. but what if you do not have any and get caught in a downpour? I have used acorns, bark off trees and even leaves. I have also used my hat once in a really good rainstorm and almost had a shot at a running deer. All have worked fine with no issues. Inlines with closed breaches really do not have issues, if you have a percussion or flintlock those are really the ones affected.