Best way to remove back glass on iPhone 5S?

I know you can remove all the components of the iPhone and buy a new rear frame and put the components in there and its like brand new, but that is expensive and difficult. I also heard you could heat the back glass pieces and remove them carefully, then place the new glass pieces in the phone with 3mm double sided adhesive. I just want to know if this is safe to heat the back of the phone and such