I remember making and using one of these for a Girls' Camp many years ago. :) They really work!
"Cut out one end of a #10 gallon can. Cut a door about 3" high and 4" wide on the side of the can at the open end, leaving the top of the door attached. Bend door upward and outward. Then slide the cut-out lid into the closed end of the can, settling it firmly there. Punch 4-5 smoke holes with can opener into the sides from this closed-top end. The double thickness of metal will conduct heat more efficiently.
The source of heat is a "buddy burner" which is made by inserting a coil of tightly folded newspaper, rolled strips of corrugated cardboard, or sawdust -- in a tuna can and soaking with melted paraffin. Each one will burn 1.5 hours. To control or put out the flame, use foil or a wire attached to the tuna-can lid."
(Source: Handout on Emergency Cooking)
