Trader, as you know the manual SHOWS someone snaking a vaccum cleaner hose all the way down the side of the package, and then sucking up the ash. It would be quite tough to slide hoses, etc. down there and not touch the refractory. My metal cover thing would sit on top of the outside of the chamber - to protect against that hose, etc. - maybe I don't understand the combustion process in that model, but I assumed that nothing was happening at that point (covering the top where the finger went in).... It may simply be that customers do not understand how fragile this stuff is - like thin styrofoam. If I was a layman, I would have a hard time comprehending that something which I would break apart with my finger could hold up to 1200 degrees plus!