Does it appear to be stuck from gunk around the switch or does it seem like an internal problem?
If it's gunk around the the outside of the switch, anything you use to try to spray on and wash out the gunk may cause the gunk to run down into the insides of the switch and and make things worse. You might make it work, but you might ruin it, too.
Don't worry too much about chemicals from the contact cleaner. Except for a few minutes after you spray it, the amount of similar chemicals from other things in your house 24/7 is so much greater than what the contact cleaner has, that you don't need to be concerned. Air the room out or do in in the garage if that makes you feel better. Try not to breathe the fumes when you spray it, but unless you concentrate it or use it all the time, they're fairly harmless.
Get the free SleepyHead software here
for information on the main alternative to CPAP.
If it's midnight and a DME tells you it's dark outside, go and check it yourself.
Take a look on your local CraigsList, around here you can find those units for less than $100 might get you the parts you need at an affordable price.
If everyone thinks alike, then someone isn't thinking.
Everyone knows something, together we could know everything.