Grills were made by embossing the stamp, breaking paper fibers, and allowing canceling ink to soak deeply into the paper. This made it difficult to remove cancels and reuse stamps. Charles Steel, who oversaw postage stamp production in the 1860s, patented the grilling method. It was used nine short years – 1867 to 1875. Grilling resulted in some of the greatest U.S. stamp rarities, including the legendary “Z” Grill U.S. #85A.