Because the coil is over-insulated, it will be scrapped when it is scratched, so it can be viewed from an alternative perspective, such as the plastic tray of the coil.
Under the same total weight, the aluminum coil should be light, so the tray will be much heavier, relatively speaking, the amount of sand in the composition should be mixed.
The test method is: licking a small piece of plastic with a fire, the taste is heavy and the burning time is short. Most of the aluminum coils, in turn, the burning time is a little longer, the taste is not very stinky, it will be a copper coil. If you want to confirm, you can Disassemble the foreskin of the coil lug and scrape a little bit of patent leather. The anti-white light should be aluminum wire, and the white with red or slightly yellow is copper wire.