This spring I was thinking about removing the burnpot on my Harman Accentra insert. The cleaning guide doesn't say anything about this, but there are two air ports on the back of the burnpot that I'm sure are filled with ash and carbon. There are no instructions for this in the book. It looks like there are 4 nuts around the sides of the burnpot, and there is probably a gasket. Has anyone done this, and should I order a gasket before I start (if there is one)?