PRE is a solvent that removes silicone and other contaminants. See here:
Eastwood.com You can get any silicone/wax remover from any auto paint store. It's cheaper too.
Not sure about the pits, but that is where the phosphoric acid helps to neutralize the rust. You could spray on the Phosphoric acid and wipe it off a few times to see if that helps. Then spray liberally with PRE. Then epoxy prime.
