Product review (5 stars): Works very well
This works great! I used a drill and started with one section then kept adding sections. Don't start with too many sections as the drill will tie them into a knot! I was able to pull junk back out of the vent with this. My vent run is about 16 feet, so I've ordered another kit to complete the whole run. What I've done so far has helped tremendously. My vent run is in the crawl space and the stuff I pulled out was cold, damp and caked so I don't see any fire risk at least down there.

More info: If using a drill, keep the speed fairly low and steady any exposed section between the drill and the vent opening with your hand. And NEVER reverse the drill! The brush and sections simply screw together and there's no locking mechanism. ALWAYS turn in a clockwise direction. Had no problems with the sections coming apart. In fact, I had a hard time unscrewing them when I was done and had to use pliers.