l,9,10 People have been picking winners in Topps' Match-the-Stats scratch-off cards using a simple tool: a flashlight.

In a dark room, they shine the light behind the card. The word "out" was barely visible on six dots, and they would scratch off the remaining three matched spots for a winning card.

The trick was revealed on the Prodigy computer network by Paul Sanford, 35, of Felton, Calif.

Topps officials Wednesday called it a "printing error" made by one of its suppliers. The company is working to correct the problem and will honor all winning cards.