|Thanks Screenplay. Should have thought GooGone when I said gooey. I took the box to a shop for tank cleaning and media blast and have got the firewall mostly clean with a razor blade and will f try GooGone and steel wool.
I may temporarily assemble with door foam strip so I can take apart again at the paint shop. While the engine was out I had towed the car to the paint shop to get the engine compartment done, but due to a leaking master cylinder the new paint got ruined. I think they will be able to do a better job with the pedal box out.