Or they could just copy the sly scam that the town of Brookhaven, in New York, used earlier this month to raise funds for booster classes and clubs in local schools.
Scantily clad women were positioned along a road holding up signs promising a topless car wash.
The signs attracted the interest of dozens of excited male drivers, who paid $5 (pound;2.50), then followed the ladies' directions around the corner to the makeshift carwash.
It was only when they had driven past a large blue tarpaulin that they saw who would actually be washing their cars: a team of shirtless male firefighters.
The fundraising event was organised for schools by the Brookhaven fire department.
"It was a little bit of a bait-and-switch," Donald Prince, the assistant fire chief, admitted. "But all the guys back there are topless."
Female drivers did not seem to mind the shirtless firefighters. However, some male drivers felt they had been short-changed. Among them was Mike Matias, 18, who was quoted by the Associated Press as saying he had been hugely disappointed when a man soaped up his car, but was glad, at least, that his $5 went to a good cause.
It's amazing what you can get away with in the name of education.