While I understand your reasoning for physically cutting metal off the coin in order to stop further deterioration, no, I could not call that cleaning. But I could see how it could be called harsh cleaning, albeit at the extreme end of the spectrum. Scrubbing a coin with steel wool to clean it is also harsh cleaning, and that method also physically removes metal from the coin. And you sure wouldn't call scrubbing a coin with steel wool conservation would you ? Do you see what I mean ? There is no difference between the two except the degree of extremity.