This refers to putting them in vinegar to bring out the date on dateless Buffalo nickels. Personally, it's a practice that doesn't really appeal to me. While it's nice to know the date, nickels that have been put through this process (including from professional products such as Nic-A-Date) just don't look all that good. Where are you going to put them? In a 2x2 album? How about a Whitman folder? I don't think so. Hence, I'll just trade out nickels like these in vending machines when I find them.
Thanks! I'm actually filling up a Buffalo book with my circulation finds... this one came many years ago. So far I've got 27 holes filled.
If you do it right (vinegar only), the coins don't really look that bad. That said, I would advise against using Nic-A-Date, as well as the vinegar/hydrogen peroxide mix as both of those methods usually make the coin look bad. I've heard of people selling the coins treated in vinegar from anywhere between 25 and 50% of their G-4 value... which would make my 21-S worth a good little bit of money. That said, I have no plans on selling it or the others as I am putting together a book of the Buffalos I've pulled out of circulation. So far I've filled 27 holes. I know of others doing this as well, and it's kind of fun, actually!