Best Homemade Camp Stove
Soda cans are easy to find lying around so it's good to know how to make the Pepsi can stove and the penny stove, but both involve fitting two halves together and it's rarely a neat fit. In fact some peope talk about sealing the two halves with super glue etc.
If you can plan far enough ahead to carry super glue and scissors you can plan far enough ahead to carry a shoe polish tin, which makes an excellent, easy-to-fill penny stove with a tight fit between the parts. In fact it can also double as a (ventilated) container when not in use as a stove.