My iphone was cracking up on the back and the screen being pushed out. I took a sharp needle and popped the battery. Gas came out and the battery went back to normal size; gluey smell -probably not very healthy but have heard of phones getting completely wrecked. Don't know if this is the smartest thing to do. Probably not if you have an aple store nearby where it'd be better to arrive with impending disaster in hand.
The battery was of course useless, but that was the case beforehand. Bought the phone used, so wasn't sure if I would have any rights of battery replacement at reduced cost.