Get a glass jar. Put all these dateless ones you got in it. Pour in enough white vinegar to cover them. Screw on the lid to slow down the rate of evaporation. Check them every day for dates and mint marks. If after a week nothing turns up, it's unlikely anything will.
Hey Brandywine.... So many of us started our collecting journey last with those old worn nickels. And there is absolutely nothing at all wrong with collecting them. They still represent a wonderful period in history..... Just be warned. Collecting these old coins is horribly addictive!
Cool old coin. I remember as a kid getting Buffalo nickels in change. I don't ever remember getting one with a date. Put it in a jar and keep it.