BE EXTREMELY CAREFULL USING HEAT, DO NOT USE A PROPANE TORCH UNLESS IT IS ON VERY LOW FLAME, I HAVE LOST MORE THAN ONE SITE GLASS EVEN BEING CAREFULL. THE BEST IS TO JUST KEEP PUTTING WD/40 OR A PRODUCT MADE BY KANO, THIS PRODUCT IS THE BEST. PHONE # 615-833-4101. YOU MAY ALSO TRY A INDUSTRIAL HOT AIR GUN.