Found this - may be useful
"Baking powder/water solution will break-down the corrosion. Trick is to get everything clean and dry. I apply the solution with an old toothbrush, then flush with water, then dry with compressed air. Protect yourself from spray, especially your eyes. To clean/polish the contact surfaces I use: emery cloth or very fine sandpaper, a fine wire brush, small knife blade, pencil eraser. Once surfaces are dry and polished, I use an electrical contact paste to prevent future corrosion. I make a practice of keeping all electrical contacts clean and protected whenever I'm doing any work on my bikes, whether they show signs of corrosion or not. I hope that helps. Good luck, and do good work."
This is for larger components - skip the compressed air
Jim Carroll