If you havent dried your stuff yet, now its time to do so. I would probably use some sort of electrical grade water displacement liquid (kinda like WD40 but safe with electronics and specially plastics) on the metal parts, pots, switches, connectors, etc to prevent further corrotion.
Aeolian is correct, a lot of stuff gets cleaned with water, like distiled water used on ultrasonic cleaners, but like Aeolian mentioned, the water that got inside your equipment is far from being distilled. So even if it may sound like fighting fire with fire, an ultrasonic bath with distilled water, perhaps mixed with some specialized electrical grade cleaning solution, followed by water displacer on the metal parts, connectors switches and pots, could fix everything.
Perhaps not the mac, but maybe the rest of the equipment. Well, if they pay, then forget everything I said.