Until this month, melting down coins hasn't been illegal in the US. But from now on, dumping your chump change in the fondue set and turning it into an ingot could get you up to five years in prison and a $10,000 fine. read more
However, some Lincoln cents have more than a penny's worth of copper in them, but it is illegal to melt them. Lincoln pennies minted from 1959 to 1982 are made of 95% copper and have about 2.5 cents worth of copper in them. read more