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Silver coin dirty again

Lord-of-PTabs

Full Member
Joined
Jan 15, 2014
Messages
105
So i found this 1931 silver Dutch coin ( im in NL).let it sit in electrolysis for a few minutes,then brushed with a soda. The result wasnt too bad but, the next day the coin was covered with black stains. Is the air causing this reaction? Can i avoid it? Vacuum?
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The next day...

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Tnx for all replies.
 
It's cause there's a lower percentage of silver in it then some other coins. A lot of Canadian silver comes up spotty cause of that..but there's really no reason to put a silver coin thru electrolysis, I wouldn't do that again in the future but if you do only do it to sterling, I'm pretty sure those marks are the other metals in the coin reacting to the electrolysis
 
electrolysis created little caves down in the coin. Must eliminate one of the variables (moisture or oxygen) to keep it from corroding again. At this point with damage done I would hot wax and buff... maybe there is something better but you need something that will stay solid in those cavities. An oil of some sort wont be enough.
 
Hydrogen Sulfide is what causes silver to tarnish. If it is the air, your coin will discolor. There are many sources of H2S - Anerobic digestion (bacteria breaking down organic matter in the absence of O2), Natural Gas, well water, industrial waste, and well, even you. Humans also produce small amounts of this gas.

Your only real solution is to clean it and put it in an air-tight container.
 
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