Agreed that silver is the metal to stack.

That said, a case can be made for nickels in a true TEOTWAWKI situation. They have intrinsic value and might be useful as "small change".

In the early stages of a SHTF/TEOTWAWKI situation, things like water and food (and ammo) would be your critical needs. But after some period of time, the limitations inherent in barter might make silver critical as a medium of exchange. But what if, at that point in time, a chicken costs a 90% silver dime? What medium of exchange would be useful for a single egg?

Wouldn't worry too much about an anti-melt law though. If things get that bad, there won't be a U.S. government around to enforce it.