I coat the sticky side with vasoline before I put them on my car and they always come off easy.
Mine say "My gun protects your freedom", "Don't take my rights because you won't control your child", "My pistol and rifle are only tools, I am the weapon", "Only criminals, dictators, and democrats fear armed citizens", and two American Flags.
I want the ones that say "Got Ammo?", "Keep honking, I'm reloading", "I shoot carjackers", and "I support the right of victims to shoot back".