Hi,
Check this article out. While it is mainly focused on Acid repair for Pinball MPUs.
the same process applies for your board.
http://www.repairconnection.com/acid_damaged_mpu.htmAlso
http://marvin3m.com/bally/index1.htmhas the following to say
Bead Blasting.
A bead blaster is mearly a sandblaster, but instead of shooting sand, it shoots small ceramic beads. This is much gentler than sand. To bead blast a board, all the corroded electronic components should first be removed that are in the effected area. Then the board can be bead blasted (after bead blasting, the board should still be neutralized with vinegar, as discussed below). Finally, new components are installed to replace the old ones.
Some people claim bead blasting is not a good way to remove corrosion, as it "embeds" the corrosion deep into the pores of the circuit board, making it impossible to remove at a chemical level. This may be true, but many commercial board repair establishments use this technique to remove corrosion (probably because corrosion can be removed quickly, with a very professional "look", using bead blasting). Most individuals don't have the means to bead blast, so it's not worth arguing this point here. But please keep this in mind.