I've been making up a necklace using 18K White cable of 0.5mm
diameter in short sections.After soldering tubes onto some of these
short sections I notice some brown staining which doesn't come out
in the pickle(sodium bisulphate).
I think the cable has been rhodium plated and wonder whether this is
what has caused the staining with the heat of the soldering.
Any bright ideas on how I should clean it up again? Thanks. Colin.