If you don't mind removing the coin from the cello, you could buy a plastic airtight and put it in there. That would offer good protection. Another option, which I think might be a bit of an overkill, would be to have the coin slabbed (although that may not be cost effective or very desirable, but it would offer the best way to seal it off from environmental factors).
Edited by spaceace
07/17/2014 09:47 am
07/17/2014 09:47 am























