Product review (5 stars): This is an essential item for every homeowner
Gardus LintEater does the job.  I was shocked how much lint was removed.  Essentially my vent pipe was totally jammed.  Very easy to use.  I chose to clean from the inside by using attachment for vacuum cleaner.  Suggest you get a shop vac, even a small  one.  It will overwhelm a regular vaccum cleaner.  Make sure to keep cleaning out shop vac as you go along.  What a difference it makes.  Previously clothes were not drying even on the highest temperature.  Now in half the time and on Medium, they come out completely dry.  Make sure to get the extension kit so that you get all the way to top.  Definitely get on roof or wherever exit to vent is, and clean out by hand any built up obstruction.  Finally if you have never cleaned your dryer, move it outside, take all the covers off.  Go to YouTube for instruction videos. Use a yard blower to remove lint and then vacuum the rest.  Take cover over off of blower and vacuum all  around.  I found  an earring in the blower unit.  You will be shocked how much lint is inside your dryer.  Plan to clean vent system every year and dryer every five years.