Ok, i researched it and found that tin foil is usually about 99.9% pure, the remaining one percent being other impurities that can burn off at a low temperature. So whoever wants to can smoke out of aluminum, but I still wont because ive seen tin foil thats been smoked out of and the entire outside and inside are singed black, it still seems like a bad idea IMHO. Also its temporary, ugly, and it heats up very quickly

edit: also if you smoke out of a soda can the ink burns on the outside and that is definatly bad for you. Thats why its so harsh