Restore the phone and take it to apple, JUST talk about the home button and nothing else. My friend accidentally spilt vodka all over his iphone 4, the home button started sticking and you could see the 30-pin water sensor was tripped, he walked in and only spoke about the home button saying it was sticking.. The Genius looked at the phone, teste the home button, didnt even check the water sensors, and replaced the phone on the spot.