An iPhone 4 in my household recently took a trip to the bottom of a thankfully clean toilet. After it was fished out and the exterior was dried and cleaned, the speakers were not working but the phone otherwise appeared to be working.
Some number of hours later, this event was reported to a responsible party in my household. After powering down the phone, it was placed in a sealed plastic bag with dry white rice for 36 hours. The rice was arranged to surround the phone.
After the ordeal, the phone is working fine, including speakers. Perhaps we were lucky. All I know is that the phone survived complete submersion in water.