These were great instructions, but have to admit this was quite a hair-raising process because of the amount of heat that was required to soften the adhesive and the amount of force needed to pry things apart. Luckily, I have a digital hot air source (Sparkfun 303D) used for surface mount electronics. The safe temperature ended up being about 200 F. If I did it again would be much easier because I know the glass piece at the top is not as fragile as I thought. So, heat gun, definitely. iOpener would be next to useless, especially to loosen under battery. But be careful not to concentrate the heat and melt plastic or make glass crack. Adhesive under battery definitely reusable, easy to peel off old battery. Go slow with the whole process and it will be successful!