You speak in contradictions. For example, a 1946-1964 Roosevelt dime has a face value of $.10 but a "melt value" of $1.2022 (today) according to http://www.coinflation.com/

The U.S. government may not like it but there is little they can do about someone melting down coinage, especially outside the country. (But don't do it -- silver coins are worth more than their melt value).

Paper money is different, of course.