I was a teacher a few years back, and we had an interesting experience with girls and bathrooms. Understand that I taught at an EXTREMELY small high school (sr. class was 22 kids). Our janitor reported that the girls bathroom mirror was covered with lipstick every night. After a week of cleaning it off, he was getting pretty annoyed. Since we have a small high school, the principal called ALL the girls out of class and had them report to the girls bathroom. She explained that the janitor was tired of having to clean up the lipstick mess every day, and that it was extremely hard to get lipstick off the mirror. She asked the janitor to show the girls how hard it is to get lipstick off the mirror. He picked up his scrub brush, dipped it in the toilet, and scrubbed the mirror until it was clean. Needless to say, the mirror remained clean after that!