Here’s an old news story. Not sure if it’s true, but it could be and that’s good enough for me.
According to a news report, a middle school in Oregon was faced with a strange problem. A number of girls were beginning to use lipstick and would put it on in the bathroom. That was fine, but after they put on their lipstick they would press their lips on the mirror, leaving dozens of little lip prints. Finally the principal decided that something had to be done.
She called all the girls to the bathroom and met them their with the custodian. She explained that all these lip prints were causing a major problem for the custodian who had to clean the mirrors every night. To demonstrate how difficult it was to clean the mirrors, she asked the custodian to clean one of the mirrors.
He took out a long handled squeegee, dipped it in the toilet, and then cleaned the mirror.
Since then there have been no lip prints on the mirrors.