4 tablespoons to a gallon of water is what i been using to neutralize it. Wipe off excess first with paper towel, then scrub the area in question well with small wire brush dipped in the TSP water solution, and wipe it with paper towel wet in tsp water solution, then wipe dry. I try to rinse and rinse multiple times. i keep 2 buckets. One for dipping and scrubbing with a wire brush, second one with a cleaner tsp water mixture. That second one is for dipping the paper towels in. Then i use 80 grit on my DA to smooth it out.
The clean pitting gets filled with a skim coat of evercoat fine scratch filler polyester glazing putty and sanded smooth with 220 on a DA so only the pits are filled. Then an epoxy primer gets sprayed over all of it.