Rodents had overrun a posh private school near New York City. So the headmaster asked a health inspector to deliver a slide presentation to teachers and students, showing how to remedy the situation, i.e., stow trash, no food in class, etc.
The following day, a teacher had her very young children write a letter to the inspector, thanking him for the visit.
One of the students wrote:
Dear Mr. Ark,
Thank you for coming to my school. Until I met you, I didn't know what a rat looked like."
Sincerely,
Bobby Jones