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Old 17th Apr 2012, 4:31 pm   #3
GMB
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Join Date: Aug 2003
Location: near Reading (and sometimes Torquay)
Posts: 3,086
Default Re: Silver dip: what's the secret?

The silver cleaning action is by thiourea in sulphuric acid.
It dissolves the black sliver sulphide, and the acid will eventually dissolve everything else given long enough. You end up with less silver than you started with.

I think they now add something to coat the surface to resist further tarnishing, hence the problem mentioned above.
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