Product review (3 stars): A Useful if Somewhat Flawed Laundry Dryer Duct Cleaner.
This is a  useful, if flawed, laundry dryer vent cleaning package, though it may be worthwhile if you have a long, complicated duct. The main cleaning unit is a set of four 36" flexible plastic rods and two brushes. The rods have metal threaded mounts allowing the rods to screw together and for the attachment of one of the brushes. After detaching the duct from the dryer the rods with brush are attached to a drill and run through the entire duct and outside vent. Unfortunately the rod has a tendency to pop out of the drill. The metal caps on the rods appear too thick to be securely held by the drill. I used a 3/8" cordless 18 volt drill with the torque reduced. Gardus should provide a "reducer" that would attach to one of the rods to improve the fit with the drill. On the positive side, the items are reasonably well made, with detailed instruction on both paper and DVD. One of the brushes can be used to clean out the lint trap vent, though I didn't find it that effective.

If you have a short, simple laundry dryer duct, you  may have somewhat cheaper alternatives to the Gardus. If your duct is made from foil or vinyl, they are not considered safe, and so not worth cleaning. You need to replace them with a stiff or flexible sheet metal duct, the former preferred.  If you already have a flexible sheet metal duct of less than eight feet, a replacement duct with pressure clamps is only about $10. With a short metal duct you can use a leaf blower to clean the detached duct, though some lint residue may still adhere to the duct's inner wall. Make sure the vent between the wall and the outside is also clean. Before detaching the duct from the dryer you may also want to run the blower through the lint trap vent--after removing the screen. Finally, you should also vacuum out the duct entrance on the back of the dryer. The Gardus package includes a couple of adapters for both a shop vac and a leaf blower, but I didn't find them that useful.