After about two weeks of burning in my new non cat EPA stove I caught a nice day today and had to pop the chimney cap off to see what I had in the pipe. I have been burning mostly at night and one 48 hour or so burn. What I found was a light brown hazing or thin dusting. I could stick my arm down the pipe and wipe it around the sides and come out with a small amount of dust on my arm that was easily wiped off with my hand. I believe this is probably OK but the top and sides of the ceramic fiber blankets were black. Is this normal? Can I clean them?