Actually, Kaowool is a ceramic fiber blanket type insulation, which is most likely what is on your door now. I would just be cautious when removing the old stuff. Ceramic fiber insulation that has been exposed to high heat can become friable (easily breaks up and travels through the air). I would at a minimum wear a dust mask when handling with it.
I work for a insulation company and when we remove Kaowool from the inside of heaters at the refinery we have to treat it as asbestos. It is believed that the ceramic fibers can cause health problems similar to asbestos.