I do not use iFixit method of using heat to get the batteries out. I fill a syringe full of methanol (pure alcohol) squirt it under the battery to loosen the glue. I then pry it out one at a time without destroying the battery. I have yet to have a failure, but I'm a working tech, I use the guides, write some, but I have to get it to work or I don't get paid ;-) I also can't take an hour using the heating method, my method takes me about ten minutes.