Soaking phone motherboard in isopropyl to fix potential corrosion
Isopropyl alcohol ("IPA") can be used to rinse water from a PCB before the board corrodes. The IPA then evaporates quickly. This works much better if you use 99% IPA instead of the "standard" 70% IPA you find in grocery stores. (The 99% is often in grocery stores, too, but is in a smaller container that costs more!)

Once the board is already corroded, IPA won't do much. You could try using IPA and a toothbrush to clean up the corrosion (since it will evaporate before causing more), but I've never had that work very well.

Another thing: Once I used IPA on a cheaply manufactured PCB and it softened the solder mask! Another reason to avoid long soaking.

Here is a related answer describing what to do if the board is only recently wet.