Remember that POR15 "likes" rusty surfaces, even better than smooth sanded ones, so you might not want to go overboard on super-cleaning it. Make sure they're smooth, but a little rust left on it, as long as it's not loose scales, makes the POR15 adhere better. This is my experience.
I also read elsewhere that olive oil gets POR15 off of your skin pretty nicely (but I can't quantify this advice!! I had to scrub skin off to get it off of me).
Have fun, it's messy but I like working with POR15. There's a lot of advice on the stuff at www.por15store.com
it's not the company's website I don't think, but a lot of questions are answered there. I'm thinking of coating my garage floor with it this summer maybe.