Cleaning steel

I have some circa 1910 Russian silver-handled knives with
pre-stainless steel blades. The blades were originally plated with
silver (or possibly some other bright white metal, but a decade too
early for chrome) two thirds of which remains, but the rest of the
blades are badly discoloured to patchy brownish-black. If there was
no plating it would be easy enough to use a mild abrasive to clean
the blades, but I don't want to risk removing any of the plating.
Any thoughts?

Jack Ogden


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                  Conservation DistList Instance 17:20
                 Distributed: Thursday, August 14, 2003
                       Message Id: cdl-17-20-016
                                  ***