I'm impressed how clean the board is after all that gunk. I would classify this as unrepairable and hazardous material like asbestos, but the result after ultrasonic bath is impressive. The corrosion residue on board between the jumper wires probably merged into the PCB material itself so it shouldn't be a problem for few years.
Of course the arc furnace is the best method for cleaning PCB's, thumbs up to Riotpack.