I smoked 3 chickens in this thing the other day, and not only did the grease can run over, but the inside of the smoking chamber is standing in grrease, and grease has come out around all the edges of the chamber cover. (The whole thing stinks) Should the smoker be throughly cleaned after each use? If so, what't the best way to do it. Is this supposed to have a gasket around the smoke chamber cover? I get about as much smoke around the cover as i do out the stack.