We have a Vermont Castings fireplace insert. Recently we lost power for a few days and the house got cold. We had the stove in use the entire time, though without the fan much of the heat went up the chimney. My son had a blanket wrapped around himself and stood briefly close to the closed door of the stove, with his back to it. In about 30 seconds, we smelled something chemical and he quickly moved away, but the blanket he was wrapped in adhered to the glass on the front of the stove. Evidently it had some sort of chemical on the surface, maybe a fire retardant, which got hot and was blown against the glass by a slight breeze when the outside door was opened. We quickly pulled it away, but it left a sticky brownish residue which I immediately tried to remove, but nothing has worked. After the stove was cold, I tried Easy-Off oven cleaner and various other cleaners that disturb the surface, but nothing has made a dent in it. It appears actually baked into the glass. I don't want to cause any more damage than has already occurred. Any suggestions?