Please be aware that Richard Binder has issued an advisory on his business Facebook page indicating he has evidence that Baystate Blue (and likely the other Baystate inks) destroys the translucent plastic feeds on Pilot and Namiki pens. He is advising people to discontinue use of Baystate Blue in those pens.
I post this because I have done the same on FPN and at Badger & Blade and I don't want to see anyone's pens ruined here either. I want to be clear that I do not regard this as an indication there are issues with any non-Baystate inks made by Noodler's, that I don't see it as a fault of even the Baystate inks, that I don't see it as a fault on the part of Pilot/Namiki, and that I actually love Baystate Blue as well as my own Namiki Vanishing Point.
I have long advised people interested in using the vibrant blue glory that is Baystate Blue to commit one inexpensive but good pen to the ink. I use a Levenger TrueWriter I purchased from Levenger Outlet on eBay for something like $15 for Baystate inks. Even aside from any advisory, Nathan Tardif has urged people to never mix Baystate inks with any other ink. That doesn't mean flush until the pen runs clear. It means flush until there is NO TRACE of the former ink.