Hey Cortez, that's a very good question, one that I am always wrestling with. Seems like for some pipes, a good smoke is routine, no matter what the blend, weather, phase of the moon etc. Whereas with others, its a rare day that you can draw a perfect smoke. No rhyme or reason that I can ascertain. For instance, I have a really nice 1948 Dunhill Shell Pot flake pipe that is rare to deliver a good smoke, despite the fact that I really love the shape. For these type of problem pipes, that don't smoke sweet, I make sure to dispel all the ghosts from previous owners by filling the bowl with non-iodinized salt and EverClear grain alcohol and letter it sit up right for up to a week or two. A pipe cleaner is inserted in the back to prevent spill of salt into the shank. Sometimes I speed this up by placing the pipes in the oven set at low at 180F, then just a few hours will do. The gunk that crusts out with the salt is an indicator of the degree to which the pipe needed to be cleaned in the first place. Also the degree of staining of the pipecleaner also indicates this. Anyhoo, my Petersons CONSISTENTLY deliver me a great smoke ALL THE TIME. The Dunhills while more high-strung are nevertheless also able to deliver great smokes, its just that I find some of them need to be matched to particular blends. But then again, maybe its just the time of day, the weather, my mood, what was for dinner etc. Pipe smoking is a mysterious game. I know one thing for sure, I don't enjoy a pipe after brushing my teeth with Colgate!!!
