Tupperware's plastic bowls sold poorly in stores in 1947. Their lids sealed only after being "burped," pressed to let air out, which puzzled shoppers.
Saleswoman Brownie Wise showed guests at home parties how to burp the lids, and sold so many that Tupperware left stores.
At Tupperware parties, a sealed bowl of grape juice could be tossed across the room without spilling.