cleaning out my eko 60 and shutting it down for the summer. i found a large buildup of hard cresote in the top chamber on both the front and back wall o top of the fire brick. is this normal??? it varies from 1-3 inches thick and is on both front and back walls, but only goes up the wall a couple inches. we never let our fire go out, and i try to stir everything up a couple times a week but the front wall is impossible to get to. anyone else have this????