From my experience, microfiber isn't really necessary. The PDMS is much tougher than most want to say and can usually handle slight scrubbing with a normal towel. I normally use the warm soap and water method and that usually works 99 times out of a 100. But sometimes there are those spots that just don't want to come out. In those instances I'll use one of our medical shop towels(DO NOT USE PAPER TOWELS. the fibers of the paper and whatnot get everywhere), dab it in a bit of 70% Iso, and then basically just massage the area where the spot is until it's gone. This way, I'm not soaking the vat is a corrosive chemical that's harmful to it. Never had a problem with it.