Patina

[Klassiker 153]

Does anyone have an inkling what the discoloration on this casing is? I don't know what the metal is, but it doesn't appear to be plated. Brass or bronze? The patina is orange and blue in patches, almost like heat-blued steel.

[Tudor 375]

Perhaps someone polished off the original plating?

[saswatch88 156]

def. brass, looks as if it was plated and somebody tried removing it using a chemical process (acids) and tried to dry it with heat and accidentally overheated it, minerals and water can also have the same affect on brass, its highly unlikely but its the first thing that comes to mind due to the purple/blue discoloration, this is a very common problem when people try to clean empty shell casing in order re-case them and make their own ammunition. The brass is treated or heated improperly.

Edited October 9, 2020 by saswatch88

[Klassiker 153]

Thanks both of you. I'm favouring the chemical removal of the original plating theory, because there is no plating left, even in the hard to reach nooks and crannies. No signs of abrasives either. I guess I could polish it up, but I think I will see if I get used to it's individual charm for a while.