Hi! I received my first TWSBI—an Eco—and I was wondering how resistant it is to staining from "strong" inks. In particular, I am looking at filling it with Noodler's Kung Te-Cheng, which is a great ink but also something that people have described as "apocalypse-proof". I have lent it successfully to people when their ballpoints (ew) would not on the signature space on credit cards so it is that kind of special and stubborn.
I don't have high hopes for its compatibility but if it has been tried and tested it would a welcome surprise.
nb. I get the whole battle scars argument but I prefer my pens to be on the side of "pristine"