What a nice thread!!!
My advise to you for cleaning those circuit boards as i clean and restore a lot of sound equipment that is full of whiskey-cola, tequila , beer and water all that mixed with tar from cigarette smoke (grouse) :
Make a mix of water with regular soap , place the boards inside scrab them with a toothbrush (you did that) then after you dry it out take a contact cleaner spray (Philips i prefer) and cover the circuit board with it and let it be it can remove all rust and salt and it wont damage anything ALSO buy a whole lot of it as you will need to spray all plugs with it to make them live forever. I tell you i've fixed many electronics that were submerged and saved a lot of car sensors that were covered with rust,salt,water,oil...
Even if you can't save a lot you still have a lot of fun doing this restoration!
Way to go man keep it up
