A poor Jamaican fisherman was shipwrecked on a desert island. He had
lost his boat, his livelihood and possessions. He was trudging round the
island in a dejected mood when he came across an old brass lamp washed
up on the beach.
Remembering the tale of Aladdin (and the role of magic lamps in jokes)
he rubbed it. POOF! A Genie appeared. A Jewish Genie. "Vey!" he said.
 
"Am I glad to be outta there. Three hundred years I bin in that thing,
my life and soul! What can I do for you my boy?"

The Jamaican asked if the Genie granted wishes.

"Wishes, Schmishes! Course I do. I'll grant you two wishes, used to be
three but I gotta think about my margins"

"Well," said the Jamaican after some consideration "I'd like to be white
and surrounded by women." "No problem" said the Genie, POOF! - the
Jamaican was transformed into a tampon. 

Moral: Never do business with a Jew - there's always a string attached.