I put a bowl of water in the microwave with a plate on top. Once the plate was mildly hot, I took it out and placed my iphone on it to heat up the adhesive. I tried pulling the plastic tab, but nothing would happen. I noticed that there is an ideal prying point on the opposite side of the battery from the plastic tab (an inch below the volume buttons). There are no ribbon cables or circuits there, and there is a cutout large enough to fit the plastic pry tool. Pry gently there against the case (once the phone is warmed up on the plate) and the battery comes out very easily. It really seems like that cutout is there just for that reason.