This is what happens if you transport cartridges per air mail. I am glad they put an extra wrapping around them, otherwise I would have to clean everything. Sadly there was a spring inside that package that is used to allow short international cartridges in this pen and that spring seems a bit rusted from the ink.
After removing the protective wrapping you can admire the unstained copper. This didn't last long though. After the first day of use the grip section started to tarnish. If that bothers you could always polish the copper back to pristine condition, but I really like the developing patina and in fact I would have to keep polishing if I want to keep the pristine look. That is just to much of a hassle for me.