For U.S. coins its illegal to melt them. But I know a number of people hoard nickles as they have a metal value close to their nominal value. If you find any pennys from before 1982, they are copper, during 1982 they minted both copper coins and copper plated zinc, and since then they have all been copper plated zinc. I know there are people hoard the pre 1982 pennies. Some also save nickles. I collect coins and there are still some old treasure out there. I have found a number of silver dimes and silver half dollars and some of the WWII nickles that are part silver. Current coins besides nickles are all worthless metal wise. Soon they will be made even more worthless I am sure. If they do change the nickle in the future you may be able to scrap them, but it could take a while.