I close badly the water proof case and dived (scuba) about 4-5 meters deep in the sea for about 30 minutes. The camera was completely flooded (was a Hero 3 Black). When return home I rinse it with fresh water and then dry it completely well and put it to the sun first for about one hour; then the best to any electronic device that suffer this kind of flooded is to put inside a kilogram of dry rice and all of this must be inside a taper ware completely close. I leave the camera for about one month inside the rice and can change the rice with new fresh dry rice if you can at the middle of the process. After that process for remove moisture my camera could take pictures and video normally. Some time later the camera began to show some problems to put it ON and OFF so was not so trustworthy and bought another Go Pro Hero 4 Silver, and leave for one year in a box the Hero 3 Black. Finally after a year I try to turn on the Hero 3 and all was correct and could use it with out problems, but only a few times don´t respond to turn on or off, so I decided to open the camera to see what was happening. I disassemble all the parts includind the lens and the sensor and wash the cards and contacts with Bencine and soft teeth brush very well. I found little salt cristals in some parts of the tarjets, the lens, the sensor and specially in one contact tape that was the cause of the error for turn on or off. Reassemble all the parts and now the camera is in perfect funtion. The battery (go pro) that was in use when the flooded occurs is completely inflated so is discarded but I had two more so was not so much problem. Hope is useful my experience. Good Luck