It’s possible, but rather anecdotal. The legendary “nic-a-silver” supposedly will lift the dates on SLQs.
Experiment...rubbing a coin that has some residue on it is just rubbing that residue all over the coin. Look at it like this, if your new car got dusty, would you rub it with a dry cloth to remove the dirt? Rinsing never hurt anything. I have seen many people advocate rolling a cotton swab over the surface. Whatever you do, be gentle.
LOL, it would be easier to find the Lost Dutchman's Mine than it is to find a bottle of "Nic-a-Silver"
Buffalo nickels are a hard metal! What tools did you use? A chisel and an engraving hammer do well. The hammer is really tiny and its amazing how well it moves metal(just wear eye protection). There are some great videos on youtube.
A dremel is a difficult tool to use. The bits dont really catch in the metal well and its hard to control and do accurate lines. There are carvers that use them-and they do great work. If you ever want to do hammer chisel engraving let me know