Heating could cause the glass to crack if not done evenly enough.
The way i did it is use a razor blade to scrape all the silicone off the inside of the seams which allowed the ones i've done to come apart pretty easily.
If its still stubborn i would use wire as suggested to work your way down the seam in a kinda sawing motion which should pull any remaining silicone out of the seam, but i didnt even have to do that on the ones i've done.