@hakui
The demonstrator I got comes apart completely. Looks really easy to clean, can't speak to if the plastic will stain though.
I actually just bought an additional 4 pack of wings at a decent price, all demonstrators. So I plan to put a different ink in each of them. I also got a slightly more expensive demonstrator from another company (same design) to try out. I figure having multiple pens for multiple inks makes the most sense. This particular model I'm hoping will be a breeze to clean when it does go empty though.
i like switching ink colors frequently so i realized piston pens, with its higher capacity and being harder to clean than converters, aren't really for me
also one of the inks stained the plastic of my demonstrator so i have to live with that too