What To Do With Illegible Coins?

These coins can be considered junk silver and sell for about $5 each.

There are chemicals you can use to "restore" the date on worn-out Buffalo nickels. "Nic-a-date" is a proprietary mix designed to do just this, but any old acid, like vinegar, will work just as well. You will end up with a "cleaned coin", but a cleaned coin is (arguably) still better than an unidentifiable slug. Especially if it actually turns out to be a rare date/mintmark.

This principle works well on cupronickel, but does not work nearly as well for silver. SIlver is both more resistant to acids, and less prone tothe work hardening and crystallization effects that alllow Nic-a-date to work on nickels. I've seen reports on forum threads where a vinegar soak sometimes can reveal a date while the coin is still wet, but the date disappears again on drying out. Nic-a-date won't work at all on silver, because it's hydrochloric-acid-based and silver doesn't dissolve in hydrochloric acid. Unfortunately, the only thing that seems to work well on restoring worn dates on silver coins is a cyanide-based solution, which is both highly dangerous and illegal (or strictly controlled, with all kinds of permits required) in most jurisdictions. Certainly not work the risk and expense, when the resultant coin is highly likely not going to recoup the cost.

Personally, I have experienced "restoration" of design features that were ground away from a silver coin with a dremel brush, once the silver was artificially re-toned. But I do not know if the "silver dip then artificial retoning" technique would work for coin details that have worn away "naturally"; I'd think if that technique did work, then we'd see it happening a lot more often.

You could spend the nickels, as someone did here:

http://goccf.com/t/430051

Guaranteed to make their day!

A local store has a box of these. He offers one to kids when they come in. Great way to gain their interest.