I would not use silicone spray, personally. It might be perfectly fine, but I’ve never had it recommended to me for that purpose.

What I have been told to use, and have used regularly for a few years is CRC contact cleaner. You can find it online or in stores like harbor freight or just about any hardware store. It’s supposed to clean and lubricate electrical contacts, and works really well.

Contact cleaner was my first thought too, I’ve used it successfully to unstick potentiometers like volume knobs.

In this case, depending on the source of the failure, neither that nor the silicone spray might be sufficient. There’s probably a spring in there which could be stuck or partially rusted from moisture (in which case a selective dose of WD-40 would help, followed by some form of lubrication). I’d try to take the cover off and take look at the mechanism first.

I’ve never done this so take what I say with a grain of salt. If you are going to try silicone spray, I would cut power to the switch first. Those cans have flammable propellants in then.

Once sprayed on it should be fine though, and since it’s indoor the silicone won’t gunk up much, though I personally prefer to use a dry lubricant to prevent dirt/dust from building up. The same company makes a dry lube can.