I have yellow gold pieces that I have soldered together, and after
leaving them in my acid to clean the fire scale off they are turning
whitish. Can anyone tell me why that is happening or what I can do to
prevent it? Is it because my pickle is contaminated? My metal smith
is using regular tweezers to pull the pieces in and out. I have told
him that he needs to use copper tongs, but he says it doesn't matter.
Any help will be greatly appreciated.