My pickle is starting to turn sterling black. ... The pickle
isn't *that* old... maybe a few months... hasn't taken on the
telltale green-blue tinge of > spent pickle. ....No known
contaminants, other than the possibility of a couple > dead
G’day Dave; Sparex, which is sodium bisulphate will not, of itself,
cause silver to blacken. The blackening of pure or fine silver is
caused almost entirely by the action of sulphur compounds on it.
Copper in sterling silver will also blacken with the action of
sulphides, but copper has a black oxide too, which silver does not.
Sparex or sodium bisulphate will dissolve copper oxides, sulphides,
and silver sulphides. So there must be some contamination of the
pickle. But you did put in that sentence about 'a couple of bugs.'
Well, for a start, most bugs do contain sulphur compounds in their
make up, which break down in acid solution over time and that is one
possibility. But if ‘bugs’ can get in what else can get in unknown to
My suggestion is that you stop buying an expensive pickle and buy the
pH adjuster sold by shops who sell equipment for spar and swimming
pools. They sell it by the pound, not by the ounce! It is the same
stuff; sodium bisulphate and is very cheap indeed. So cheap that you
can economically replace it much more often, but even so, you should
keep the pot covered when not in use. – Cheers now,
John Burgess; @John_Burgess2 of Mapua Nelson NZ