I'm a newbie here. After reading thru many posts on this site, it seems to me that the general consensus is that it is a big NO-NO to clean coins. Is there a safe way to clean coins to just get dirt and corrosion off but still keep the tone of the coin. I'm not wanting it to make it look new, I just want some of the nasty stuff off of a few coins. Alcohol or Acetone maybe....??