DONT heat it up. Useing rubbing alchohol, WD40 or Goo Gone works best. Rubbing alchohol actually works very best. Then just take something like a toothpick and work around until you loosen it up. DONT use METAL against your glass! If it is a good piece of glass with diffuser, etc, dont heat it and dont break it! Use softer materials than the material you are working...