looked at the coin guide site on the fun time guide. So much great info listed however one last coin I’m trying to understand. On his site he said a coin may be an error if it has a reeded edge and still blank. However how would you determine that with a nickel? Also is there such a thing as a soft strike? I have a Nickel that I know has likely been sanded down. What should I look for to tell me that it has been sanded vs it being an error coin? Posting a pic if anyone could help educate me on this I would be grateful.