Product review (5 stars): If you suspect lint buildup for wet clothes, this thing will fix it fast
This thing worked great!  It is every bit as good as the other reviews say. Make sure your vacuum has a clean filter and an empty barrel. Not only will it help the cleaning with more suction, you will see the massive amount of lint it removes when you open it up.  I cleaned a vent that I had NEVER cleaned in 13 years. I used the entire length of it and removed about  probably half of a 12 gallon vac. tank full of lint. I also cleaned the filter once in between to assure good suction.
No more damp clothes or having to run at long times or super-hot temperatures. The dryer dries under normal settings again!