bath if too agressive will damage the latch and make the switch useless.
isoprop is good but wont last very long.
we have done quite a lot of experiments here at funky junk and we found that washing the switches with warm water (while upside down) and rinse them various times completely cleans the crap in there.
after that let dry for a couple of days, spray some EML in it and you are done.
Mattia.