Just to show a lot of verdigris, very impressive, came from the same box.
My guess is these rounds and clips were coated with a thin layer of something like beeswax which over the decades has resulted in the formation of verdigris. I wonder if this box was stored in a leather ammo pouch for a long period of time as close contact with leather will sometimes cause verdigris to develope.
Very good guess. I bought a dozen of these boxes and they all came like this, no leather.