This might sound like a bad idea, but it will work better than the rice method which does not remove mineral deposit or salts (not just table salt, all the other salts found in water). Chlorine from swimming pool and spa are the worst. When you drop your phone in the pool, immediately remove the battery. Don't put it back in until you have completed this process and don't delay. It's no guarantee with any low voltage circuit like your phone, but it is a good thing to try. Water is actually a very good insulator (doesn't conduct electricity) water containing what is called dissolved solids is a good conductor. This is the water people invariably drop their phone in.
Having said all that, here's what you can try:
1) purchase some deionized water and some 99% isopropyl alcohol (rubbing alcohol).
Use twice the amount of alcohol as you use water. (If you use 1 quart water, use 2 quarts 99% isopropyl).
Now the scarry part:
Deliberately drop your phone into the deionized water and soak it for about an hour.
You want to diffuse the deposits on the electronics in your phone into the deionized water.
The circuits may likely already be damaged -but sometimes they are just altered.
The longer the battery is in, the more likely the damage is permanent. The "dirtier" the water, the same is true.
Back to work:
Once you have soaked the phone free of impurities (remember, no battery), shake as much water out of the phone as possible but do not dry it out.
Now immerse it in the isopropyl alcohol for about 30 minutes.
Shake the phone out again and place it in a warm place (75 to 80 degrees) for a good two days.
The battery is probably okay, just wipe it off with rubbing alcohol.
Install the battery and charge for about four hours before you try turning the phone on.
IF IT WORKS, BACKUP YOUR PHONE

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If it was a swimming pool, your chances of success decrease more radically the longer you wait (the clorine oxidizes the the printed circuits).
PS: The isopropyl alcohol is non conductive and evaporates without damaging anything.
Good luck to whom ever resurrected their device.
-e