Thanks for the advice, as I am new to this site.
NGC has a conservation department that will professionally clean coin, they can do it but of course no one else can? Some coins are just best left...
Of course your right not to put ammonia on a valuable coin, this isn't!
If the coin is not valuable but more common, it would be ok to use "Coin Care" on the coin with a cue-tip. Yet that does not always work. Because...
I have one of the Medival Grosso coins not sure the exact year as it is undated as far as I know but have it listed on ebay.
So much for tracking.
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