I melt a lot of pop cans, i find them to be ok, they mainly vapourise if you dont plunge them into the molten metal once you have some formed, i get better results from the ring pulls,but it takes a milliion to get a decent bar size. But the best is to goto a Scrap Yard and try and get some bent up alloy wheels, they are good cheap and plenty of Crazy Drivers out there, so theres plenty of supplyi have a bunch of aluminum and wondering what quality you would get out of a melt