A grill is an embossed impression created by a miniature "waffle iron " that breaks the paper fibers of the stamp. In theory, these broken fibers would absorb the ink cancellation and prevent reuse. In practice, the grills weakened the stamps - making them prone to tearing where the grill marks were implanted. The use of grills was discontinued in 1871 when more permanent canceling inks were developed. The U.S. was the first country to issue grilled stamps.