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In my experience, water left in the device will corrode it over time - wet phones are best immediately opened and cleaned, even if they're working, in order to ensure that they keep working.

The internals are confined enough that the water droplets will be unable to drain themselves out. They just sit there, slowly turning the circuits into mush.
 
I will wait until all the circuits turn to mush there's no rush for me to go out and utilize my AppleCare Ahead of time....there could be another type of accident before the circuits totally corrode!
 
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