Reminds me of a joke I got by e-mail recently about a school where girls were kissing the mirrors after applying lipstick. The principal solved the problem by having the janitor show a group of the girls how much effort it required for him to remove the lipstick smudges from the mirrors. He demonstrated by dipping a plunger into a toilet and scrubbing the mirror with it.
There were no further lipstick smears seen on the mirrors.