Lesson learned: Do not use orange/red inks with white Pelikan barrels. To be fair, I was using a pretty excellent ink: Colorverse Golden Record. When I finally cleaned by Pelikan M400 Tortoiseshell-White, there was a coat of ink caught between the barrel edge inside the section. Strictly speaking, it could have happened with any Pelikan but because the body was white, it was prominent enough that I knew would stain forever if I did not clean it out. I ended up spending about an hour with a blunt syringe and water pressure to push the ink out. So far, I’m about 85% there - I don’t know how I can possibly get the last bit out because it feels like I’m just pushing it round and round. Foiled by physics again!