How to fix "No Service" after being dropped in water?

I wouldn't say it's due to water evaporation that saved it, since when the liquid has evaporated, it leaves behind minerals which cause corrosion, which is why you have a higher success rate on a device that's freshly wet, than a device that's been left to dry, some devices that work after liquid damage only work because liquid didn't get in a location where it causes major damage, or hardly any liquid got in to begin with.

It's a bad idea to let it dry or use a dehydrator, as using a dehydrator will just speed up the corrosion process.

I completely agree that you should get it to a professional that can clean the logic board of the liquid and any corrosion on the board. :-)

Why are you debating semantics here Ged? If it didn't work with water in it, the water evaporates away, and then it works...then the water evaporating is why it now functions. The minerals left behind can cause damage, but not like you're describing. They only cause damage if the phone becomes wet again because they increase the electrical conductivity of the new water by making it saltier.

A person doing it at home doesn't have access to an ultrasonic bath....a food dehydrator is the next best choice for at home repair. It doesn't speed up the corrosion process, as the corrosion is the result of oxidation, not the salts. The dehydrator is increasing the rate at which the water evaporates, which in turn decreases the amount of oxidation that can occur. A food dehydrator will mitigate the damage the water is able to cause. That why all board warmers have a fan in them, to move the high humidity air off the board as it warms. They're the same thing as a dehydrator.

"A person doing at home doesn't have access to an ultrasonic bath"

Which is why I said in my answer "your best bet is to get it professionally cleaned at a repair shop that uses ultrasonic cleaning"

Putting electric in to anything with corrosion will cause shorts, damaging the phone further.

I also gave tips for people at "home" using isopropyl alcohol, and a toothbrush to clean up any liquid, or corrosion in the phone, these are easily obtainable.

I'd rather go out and get those, than leave my phone in a dehydrator, I'd say you have a far better chance of your phone working using isopropyl alcohol and a toothbrush, than leaving it to dry in a dehydrator.

I would leave it in a dehydrator if the liquid was pure, but unfortunately, that's not what happens, people don't drop their phones in to deionised water, so minerals are left behind, regardless of how you dry it, I've seen phones been put in dehydrators, or on the radiator, or people using hair dryers etc. Most of them just have corrosion, and don't work.

If a phone is brought in, still wet, that hasn't been charged, then the success of getting that phone working again is extremely high, however, a phone that has been left to dry, charged (electrolysis), or is dried out in other ways, have a less successful percentage.

Board warmers, are mainly used after ultrasonic cleaning, you don't stick a board that's just been soaked in toilet water in there, nobody in this industry would do that, so why would you do that with a dehydrator?

You have to use Deminaralized water and soak the board in it and then use >90% isopropyl alcohol