Use isopropyl alcohol to clean the board. Masking tape to cover chips, ports, pins & any heatsinks you can’t remove. Apply silicon coating from a spray can , go light a few passes. Test the tape to make sure it leaves no residue, you can get special tape for electronics but a good quality decorators masking tape works well and you’ll save a few sats. The removal of the corrosion is something we wouldn’t do in house, you can end up digging out quite a bit of board before filling it. Do you have a repair shop locally ?