If you are going for show and don't want to sell them and don't mind them not being worth certifications ever again then simply mix up some salt and vinegar, place the coin in the solution for a few minutes and then use q-tips, if you have a stubborn spot, place it back in the solution for a few more minutes, then q-tip scrub again. Dab it if you are attempting to save some petina or what have you, but this definetly removes the mint from coins, which when a coin still has mint on it; It shows one of two things
1. The coin was never circulated which is the case if all the other coins with it are the same year of course, that's called a mint roll in America meaning that it literally was rolled up from fresh sacks of coins from the mint by typically the Armored Car companies. Some people using sophisticated equipment try to clean coins to pass them off as Pristine and UNC when in fact they were AU coins that were cleaned which with a trained eye and an understanding of metallurgy is rather easy to spot. The metal on a cleaned coin in the fields will look kind of grainy or pale it is not a rough look to the metal but getting very close to a rough look compared to a true AU or UNC will look smooth, the metal grains will glisten in the light and the grains will almost look like specks of gold flakes if you will when it comes to pennies. Quarters will exhibit a greenish tint sometimes when they have been cleaned, that will kinda get a dingy yellow, nickels almost seem to get like a light olive tint to them…then of course it all depends on what they have been cleaned with.
2. It was barely circulated or possibly from a collection and very well could be UNC.
This I can tell you friend, if you are going to try and sell them one day do not clean them with a single thing, the company you send them to for certifications will handle that for you if you wish, but my word of advice to you if you are going to value is to take those things add them into rolls or however you can exchange them and go exchange them until you find some better ones.
Now with all that info and you still don't mind and really like these coins and want to see them on your desk everyday or something and don't want to pass them down so your grandchildren may have a shot at some big paydirt then after you have cleaned them with the salt and vinegar solution and have buffed them until they look absolutely gorgeous and you don't want to put them in plastic slips and would rather have them in a glass case so you can handle and qtip buff them every now and then….Get a bottle of the HOPPS brand gun oil or some Rem Oil and put one drop on front and on back and pinch it with a cotton t-shirt and one more final q-tip bufff and that bad boy will glisten nicely.
