In the center of an 18″ x 18″ square of heavy or doubled foil, place one teaspoon of oil & one teaspoon of popcorn. Bring foil corners together to make a pouch. Seal the edges by folding, but allow room for the popcorn to pop. Tie each pouch to a long stick with a string & hold the pouch over the hot coals. Shake constantly until all the corn has popped. Season with butter & salt.