Tim, FWIW, I had a small job to repair about 30 industrial power supply
boards that were fitted with two Keystone PC mount twin AA cell holders
for backup nickel-cadmium batteries. As you suggest, the outgassing and
occasional leakge from the cells ate up the brass of the contacts
through the nickel plating causing the holders to fall apart. What
board corrosion there was came off with a scrub of soap and hot water.
I replaced the Keystone holders with a decent quality Tiawan plastic 4
AA cell holder spaced off the board.

I find that the blue corrosion [and white crystals] from regular
alkaline cell leakage also comes off well with soap and hot water.

Neil S.