Tabasco sauce
During the Vietnam War, Brigadier General Walter S. McIlhenny issued "The Charlie Ration Cookbook". (Charlie ration or "C-Rats" was the name for the field meal then given to troops.) This cookbook came wrapped around a two-ounce bottle of Tabasco sauce in a camouflaged, water-resistant container. It instructed troops how to mix C-rations to make such meals as "Combat Canapés" or "Breast of Chicken under Bullets." Soldiers also requested their families to send them Tabasco sauce in "care packages" from home.