OK, old joke.
The mohel (the guy who does jewish circumcisions) is retiring after 40 years, and all this time he's been saving up the foreskins. The mohel thinks to himself "What am I going to do with these? I know, I'll take them to Moshe the tailor and see what he can do." So the mohel takes all the foreskins to the tailor and asks "So Moshe, what can you do with theses?" the tailor replies "Leave'em with me Chaim and I'll see what I can do. Come back in a week." Next week the mohel goes to the tailor and asks "So Moshe, what have ya got for me?" and the tailor hands him a wallet. "A wallet!?" the mohel yells "I bring you all those foreskins and all you can make is a lousy wallet!?" Then the tailor tells him "Chaim, Chaim, calm down. Rub it and it turns into a suitcase."