I second everything what has been said about removing caps and cleaning. The only thing I would add; after scrubbing the boards with soapy water, followed by alcohol and drying in the sun or in the oven, I spray the affected area with PCB lacquer. This depends on damage severity, but on occasion, I found that electrolyte soaks in to the board creating high omic resistors between the tracks consequently the problem may reoccur later, especially in higher humidity.