Hi, I recently started using some copper sheet (C101 oxygen-free H00 alloy) that reacted in the sodium bisulphate pickle. The reaction revealed itself when I took the sheet out of the pickle and started neutralizing with baking soda. The copper started “shedding” bright yellow pigment - to the point that my hands were bright yellow as well - I had to wash them with soap to remove the yellow stain. When the metal dries it almost looks like it has been treated with liver of sulphur.
In decades of work with copper - all conditions being basically the same - I have never experienced this. I asked the supplier and unfortunately I purchased the material a few years ago and health and safety data are not available any longer for that batch of alloy. I am making an assumption that the copper is the alloy I have described - which, when I research the allow - they describe it as being 99.95 pure.
What is it? Cadmium? Any ideas or similar experience?