I went outside and i noticed this on the outside of my chimney flue. I have been burning non stop for a couple weeks and a total of 3-4 weeks total with the difference being more sporadic based on temps. The first 1.5 ranks i went thru were seasoned hardwood for about 15 months min to 24+ month as it was a mixed pile. The most recent rank i have noticed this on as far the black goo on outside. It was less seasoned and more of a 3-4 months blocked and 3-4 months split and it was a maple i believe. That being said my moisture meter didnt register anything other than low moisture. Is this something to be concerned with or is it a case of looks worse than it is? I figure i have another 1.5 months of burning. About once a week i sprinkle the creosote destroyer powder into the firebox . Can/should that be cleaned off the flue? Also just for reference the crown i did a coating on and dyed it black so don't be concerned by the black crown part. That being said it does appear to be coming down the side of the brick. Any help is appreciated.