Product review (5 stars): wow
1. clean vent cover underneath (mine was a metal 2port screw-in type on the roof. underneath was like a lint helmet. i was worried about the screws, that the brush would get caught in them from the other end; it didn't). put brush and extension in hole first, then put other end into the plastic port for vacuum and extension.
2. use variable speed drill, if you have one (you can pay attention to the drill's speed, and move backward, then forward, if it slows down due to lint resistance).
3. pay attention to the sound/vibration of the vacuum for lint obstruction amount. the hose can hang, if it's too small diameter... just keep it away from the wall for more suction power (also you can wrap hand around port in between cleaning, for more suction).
4. the brush will move backward and forward in the pipe, with little pressure while drilling.
5. i used electrical tape on each joint as the drill reached the port. the tape would catch on the lip of the wall when i was exiting, but i would just take off the plastic port and move the extention a little with my hand as i was drilling, then replace the port.
6. i used 2 pliars to tighten joints (just turn only the new joint so not reversing direction). to avoid reversing drill direction, never put the drill in reverse for anything. always remove the auger from the pipe with the drill in forward direction (refer to #4). remove extension from drill before unscrewing (with pliars) from other extention.
7. i knew i hit the end, when the new extension kind of twisted and wouldn't really go forward. (i had to buy the extension kit, using 6 poles altogether).
8. you'll know it worked if your dryer area doesn't get humid, the dryer stays normal temp for a dryer, and your clothes take less time to dry (mine takes about 35 mins now). ps, my other dryer was old, and i thought it was burning wires cause it was old, but now it may have been because the vent was blocked, so it was overheating.