Okay that one is new to me, but it's addressing a fairly specific problem. I was referring to
http://www.law.cornell.edu/uscode/text/18/331, which is older and more general. I know of many pawn/coin/collector shops which actively buy silver quarters/dollars and copper pennies for the purpose of melting them for the metal.
common practice for jewelers. If you can find a reputable legit jeweler, and have foreign coin to sell - they'll usually pay a little more for it because it's not illegal to melt them.