Hello everyone,
I'm an electronics engineering with many years experience and lots of time spent at sea in small yachts. So I've seen devices get salt in them. So here's my two cents worth:
First up, salt is not very soluble in alcohol. But it is in water. To help you can use a 50/50 alcohol/water mix. If possible don't use anything put pure alcohol.
The conductors in the small scale electronics are so close together that surface tension prevents movement and keeps the moisture between the conductors and this is where the salt remains after evaporation.
Professional services who clean things like this use water with a surfactant (component of detergent) to break the surface tension, then rinse that (probably with water/alcohol. Alcohol also acts like a surfactant. Most electronic boards etc can be completely immersed in a cleaning solution in a ultrasonic cleaning bath. I would not do that to the sensor it is probably a bit fragile. Also be aware that the alcohol will remove some oils which may be necessary with some moving parts. So re-lubrication with a non volatile lubricant may be necessary if you do this.
Drying is done in a vacuum chamber. Instead of a vacuum chamber you can use a sturdy plastic bag hooked up to a cheap diaphragm vacuum pump. This can be assisted with gentle heat perhaps from a lamp.
Even tiny amounts of salt remaining will eventually cause problems.
Another issue is that the ingress of water means that algae etc will have been in the mix. So these little blighters will start to grow like fungus on your old lenses. Alcohol and a thorough drying helps alleviate this part of the issue.
I have successfully saved the odd smart phone after a dunking. You must be patient. Like waiting for election results !