Don't know if any of my ideas will be helpful as you're in the middle of the job, but here goes anyhow:
-More aggressive claying
-Decontamination system, claying while the acidic step is dwelling
-Fairly aggressive paint cleaner/polish applied by machine (won't be perfect but will help)
For future situations like this I'd keep a decontamination system on hand. When you need it you need it.