Well, the only thing I really noticed is that I had about an inch of cresote in the single wall last week when I changed the cap. I had burned about 6 pick up truck loads of unseasoned wood through it and every other day I would throw in an aluminum can. the casing was pretty clean, just not the single wall pipe I just knocked on it like knoking on a door and it fell right off, Now I am completely burning coal, 7 days so far w/out having to relight it.
