I've been working on a couple A2000 motherboards, one with battery damage, so corrosion is very much on my mind lately. I would use a good PCB cleaner. The best is Tricoloroethane, which is probably not available anymore, but I'm sure there are modern equivalents. I use the solvent with a firm toothbrush and scrub as hard as I feel is safe to get all the gunk off.
