I dropped my iPhone 4S in a bowl of Beef Stroganoff Hamburger Helper. I thought my phone was toast. After reading a forum about how to clean your iPhone if it ever got any greasy fluids in the speaker, someone suggested I use a can of compressed air, and much to my surprise, the sound came back and IMHO, I think it sounds clearer. This may be a late answer but I hope it will help anyone else that would run into this problem. Good luck!