Bad news: Your cellphone’s warranty won’t cover water damage—if you drop it in the lake, its life rests in your hands. Take out the battery and SIM card (what the card stores is often more valuable than the phone), dry everything with a paper towel or a soft rag, and then bury the phone and battery in a bowl of uncooked rice overnight. Still doesn’t work? Try an electronics desiccant, such as Bheestie Bags.