Pink castings

Pink castings? Add a little peroxide of hydrogen - hydrogen
peroxide- to your pickle and warm it with the casting lying in it.
The pink which is almost certainly copper, will be oxidized to copper
oxide by the peroxide and that will be dissolved by the pickle,
leaving a silver surface.

Cheers for now,
John Burgess; @John_Burgess2 of Mapua, Nelson NZ