According to a news report, a certain private school in Victoria,
recently was faced with a unique problem. A number of grade 12 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 to the mirror leaving dozens of little lip prints. Every
night, the maintenance man would remove them and the next day, the
girls would put them back. Finally the principal decided that
something had to be done.

She called all the girls to the bathroom and met them there with
the maintenance man. 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 had been to
clean the mirrors, she asked the maintenance man to show the girls
how much effort was required. He took out a long-handled squeegee,
dipped it in the toilet, and cleaned the mirror with it. Since then,
there have been no lip prints on the mirror.