I was using Waterman Intense Black, which writes really smoothly but is not waterproof. I've been trying a Noodler's Bulletproof Black which is a bit more water

I was using Waterman Intense Black, which writes really smoothly but is not waterproof. I've been trying a Noodler's Bulletproof Black which is a bit more water-resistant, and so far it's okay - and the bottle was about the same price as a similar-sized bottle of Waterman. I want to see, however, whether I have any problems cleaning the pens (piston-fill) with the Noodler's.