I cast two pieces , an orchid and a rose, in fine silver, since I enamel
these silver flowers. Using centifugal casting, melting the metal with a
torch --- they were cast separately, in two flasks. The rose metal looked
normal, silver, while the orchid metal was dark, evenly black. I have been
trying to remove the black surface with pickle and an hour in my tumbler
,with little improvement. Any help and an idea of why this happened would
be appreciated.