How To Discriminate Foil/Coke/Iron on a Cscope 6MXI Metal Detector and either hear it as a mid tone (foil, coke) or low tone (iron) or choose to not hear it. A good target such as a silver hammered coin or Gold ring, Roman Bronze will always give a high tone.
IMHO you can't beat a good tone machine like the Cscope 6mxi, no target ID to confuse things, just use your ears!