Switching from Neutral to selenium. Do I need new carts?

I’ve been using Neutral P2 Piezography Inks in a P800 printer. Now I want to use Selenium for PiezoDN. Do I need to buy new carts or can I flush out the carts I have and fill them with selenium? If so, how do I do it?.

PiezoDN will work just as well with Neutral if you want to stick with that btw.

re: selenium
You do not need to clean out the carts. Just empty them (roughly) of the neutral ink and fill with selenium and run 3 heavy cleanings if you need the new ink fully through the head before calibrating your darkroom.