I'm just wondering what brands of inks are generally easy to clean from fountain pens. From what I've tried, I've noticed Iroshizuku and Waterman inks are really easy to clean. I used to think Diamine was easy as well, but since they have such a wide array of inks, some of them stain pretty hard. What are some ink brands/inks that you've used and have noticed are easy to clean? Thanks, Suji.