OK, so it was worn dateless. Acid showed it is 1916-S. No real value, but nostalgic for me, and it's not often you find a 107 year-old coin in circulation these days.
Earlier this year my son and I did some roll searching and we found two of them. I was really surprised. I think they were both in the 30s though.
I received an 1863 V nickel cashing off a customer at the McDonald’s I worked at. No rays, but I wasn’t complaining.
I have about 200 Buffalo Nickles that my father left me. About 30 don't have a readable date on them. I would like to know more about how you used some type of acid to use so that I can see those dates. I've had them since 1996. I didn't get my part of his coin collection until my mother passed in 2005. When I got my share of the collection, I went through them all. I went to coin stores and thrift stores, and any other place they might be. I was retired then and needed to find a way to keep me out of my wife's hair. I built model airplanes for many years. The resulting airplanes were either sold or given away. When I got interested in coin collecting, I had about 3,000 models sitting on the shelf. I put an ad in the Fine Model magazines. I got about $2,500 for the models and I put them to better use. I didn't get into a buying frenzy buy coins with them. I bought magazines about coins. There, I learned a great deal from many people, some professional, some hobbyists, and others that just like to look at them.
I use a product called "Coin Date," made and distributed by Garry's Coin Company from Mooresville, N.C. Unfortunately, I bought my 2 ounce bottle about in 1963, and I only have about a third of it left. It is some sort of acid, but I'm not a chemist and my bottle doesn't say what it is. I have learned to put only a tiny amount on the date portion of the coin. (The original instructions said use three drops on the coin, but that left the entire coin rough looking.) For this particular coin I barely wet it, then rocked it back and forth until the dark acid became clear (about 15 seconds), but there was no date, so I repeated the process for about another 15 seconds, then rinsed thoroughly in running water. (Distilled would be better, but I'm cheap and tap water is good for old nickles like this.) I'm sure there are similar formulations out there for sale, but I haven't needed to buy any since 1963 so I haven't looked. Check with your local coin dealer if nobody answers in the comments here.
You can purchase a product called "Nic-A-Date. It definitely restores the date but unfortunately if you are not careful it can affect the entire coins value considerably. Good luck.
Nic-A-Date was ferric chloride solution. You used to be able to buy the same stuff by the quart at Radio Shack for etching circuit boards, back when you could go to Radio Shack. You can get the same results with white vinegar and patience. Better results, actually -- vinegar doesn't stain the coin. I prefer soaking the entire coin; it restores details elsewhere as well, it leaves the coin with a uniform appearance, and since any "restoration" trashes the numismatic value of the coin, in for a penny, in for a pound. One exception: if the nickel has a raised mound on the reverse instead of flat ground, you already know the date is 1913. No point in abusing the poor coin further.
Keep an eye on it the first time. It's not nearly as fast as Nic-A-Date; it may take an hour or more (but check more frequently than that). Rinse a couple of times with distilled water. If your tap water isn't terribly chlorinated, you can use that for the initial rinse, but I'd still do a distilled-water rinse last. If you forget and leave them for a couple of months, you'll get copper-colored coins that are distinctly smaller, and once again dateless. (Don't ask me how I know. )