I swept my triple wall simpson Duravent chimney for the first time today (Burned 2 seasons without cleaning it, I know thats bad). Cleaned from the top down after removing one air tube and the baffles in my Englander NC-30. I got very little creosote, except for some at the chimney cap and top three feet. When I was done i noticed a small amount of black powder at the base of my pipe where it connects to the stove. I am using double wall stainless inside so the dust dropped through where the air space is located. Am I assuming correctly that a small amount of creosote came up through the joints as I pulled up on the cleaning rod? All of my sections are screwed together so I dont think there is any chance that any sections could come apart.