Did you know that from the years 1946-1964 US dimes were 90% pure silver and 10% copper? They stopped making them that way in 1965 but you can still come across those old coins. I think my Dad has a pile of them he has saved through the years.
According to coinflation.com those Roosevelt dimes have just over a dollar's worth of silver. Yeah, not going to buy you a villa in Italy or anything, but its probably worth keeping an eye out for these babies in your change pile.