I usually use CRC electrical contact cleaner…pull the switch out….spray the hell out of it and click it on and off about a thousand to see if they break, if they break Aircraft Spruce is usually the answer…if they feel good after a good blowing out with air nozzle and excercise, then you’re generally good for awhile. I have one on my helicopter I did that too and it’s been working for ten years!
Good luck.
