But its not on the battery area. If you're looking down at the mobo, its on the bottom right area, close to where the mouse/joystick would be plugged in. Is that normal? Just brush it off I'm assuming.
Haven't seen that before, post a photo if you have one. Might also be liquid damage if something has somehow spilled into the port opening in the case.
As for cleaning the board, isopropyl alcohol is the standard across the electronics industry. Easy enough to get and safe to use.
I've had countless boards in for repair with all manners of crap spread over them, from WD40 and petroleum jelly to lemon juice, vinegar, baking soda, citric acid, you name it. Seems there's a theory where if it comes from your garage or kitchen cupboard, it somehow performs miracle Amiga repairs. There's that theory that household substance x neutralises corrosion, which is probably true if it was used in exactly the right proportion in exactly the area of corrosion. Else it just tends to make a bigger mess. Isopropyl works fine.
