The concave bottom of these cans is designed to give strength to the container. It is possible to polish this surface to a high sheen to create fire. The curved reflective surface is able to collect the sun’s rays and focus them to a single point, igniting flammable tinder.
Once you’ve found an empty pop can, utilize materials you have on hand to polish it to a mirrored gloss. If you have the 0000 steel wool – the finest grade – you will be able to accomplish this with just a few minutes of rubbing. You can also burnish the surface with a baking soda paste, toothpaste or a paste made with scouring powder.
Once this is accomplished, you’ll want to finish with a polish. To polish the surface you can rub it with a bar of chocolate, crayons, candles, Vaseline, or any other waxy material. Apply the material to the bottom of the can and rub with a cloth, repeating this process until you’ve gotten the desired effect. A word of caution, don’t eat the chocolate after it is used for this project as it will have absorbed the aluminum a known toxin.
When the surface has a mirror finish, point it toward the sun. To find the focal point, hold a small scrap of paper between the can and the sun, moving it closer or farther away from the can until the sun’s rays are focused into a small dot of light. Visually mark this spot and hold your tinder there until it begins to smoke and then flame.
You will need about an hour’s time to polish the can’s surface. Igniting your tinder will take less time, depending on the quality of your materials.
This article is provided for information only. The reader assumes all risks and liability in the implementation of these methods and is urged to use common sense and sound judgment in its application.