yeah man theyre safe as long as you remember to keep the bulb at least an inch if not two above the flame. dont let the glass touche the flame, that will jsut turn the thc into smoke, making the "vaporizer" pointless.

also, use a candel, not a lighter cuz it takes a few miunutes for the vapor to appear and you shouldnt ever hold a bic on for longer than 30 seconds cuz it can overheat and blow up