Rotlund? Midwest? I'm looking for a MANUAL cleaning kit. Seems like screw in rods and brush is about $59-60+ or more.
I use our soot eater from bottom up when I clean it, the drill does not work at that angle, I just twist and swoosh, the stuff falls off. That said we are very low humidity and do not get wet black stuff you mentioned out there. The other 1/2 of the time husband uses the drill on top down.
I used a LintEater kit. Worked just fine w/ the 4" exhaust I had. Just never turn the drill in reverse or you take a chance of the brush unscrewing while still in the pipe.....keep it going clockwise while pulling it out.
I bought the Rutland extension rods and a 4" brush attachment off eBay for about 60% less than the Home Depot or Amazon combo found on their websites. Forget about finding these accessories in the stores... the brush size that FITS the threading. Save yourself some trouble and just order them online. Beware though that Rutland, for example, sells a flue brush that is 4" in diameter but in different thread sizes.