Quoted from YeOldPinPlayer:The cleaning process for alkaline is different than for acid.
Doesn't one clean alkaline corrosion with an acid?
https://pinside.com/pinball/forum/topic/terrybs-guide-to-repairing-alkaline-battery-damage
Yep, thanks terryb
My 2 cents, get a board from barakandl like FatPanda suggests.