Shave and a haircut
A little old man walks into the barbershop for a shave and a haircut. He asks the barber, "do you think you can get all my whiskers off? My cheeks are so wrinkled from age."
The barber gets a little wooden ball from a cup on the shelf and tells him to put it inside his cheek to spread out the skin.
When he's finished, the old man tells the barber that was the cleanest shave he's had in years. But he wanted to know what would have happened if he had swallowed that little ball.
The barber replied, "Just bring it back tomorrow like everyone else does."