What kind of tongs are you using to insert & remove the item? It
should be a plastic, wood or copper tong. Anything else will cause
an electroplating action that plates the item with copper.
Actually, stainless steel is OK, too. The iron in stainless steel is
bound in a way that renders it chemically inactive. That’s why it’s
stainless. I’ve been using stainless steel tweezers and binding wire
in my pickle for years with no problems.