Tinplate can is the informal name for the thin metal cans used to store goods, most often preserved foods. Tin cans are commonly made of tinplate, which is tin-coated steel or tin-coated aluminum. Tin, the metal, is used as a coating to prevent rust, but it is rare to find a “tin can” made purely of tin. However, there is a method to identify tin.
Place the magnet on the tin can. A tin coating will still be slightly magnetized. If the metal is not magnetic, you can be sure it is not made of tinplate coil. If the metal is magnetic and also has a silvery color, move on to the next step.
Put on your safety goggles and protective gloves.
Mix a small amount of lye with hot water. Lye reacts violently with water and will explode if you use too much, so test the mixture with extremely small amounts of water and lye first.
Place the tin can in the mixture of lye and hot water. If the can is tinplate sheet, it will start to bubble.