Boyscouts taught me how to cook hamburger on coals on a leaf. pat out hamburger patty then put slices of potato on each side of the patty. Sit on leaf on coals only. No flames. Allow to cook. leaf burns everywhere except where the potato is. You can also cook eggs like this put in a half of an orange peel. Slice orange in half, scoop out orange slices. Crack egg and put inside orange peel half and sit on coals. Note. If you cook with a pan on an open flame or coals you can cut down on the sooty cleanup by covering the underside of your pan with liquid dish soap.