Product review (5 stars): Remove the 4 screws from the casing that the filter sits in to get better access to remove the dirt and lint
It took two replacement filters and reading these reviews to finally figure out that I really did have a huge amount of lint build up below where the filter sits.  Get a flashlight and look way down in there.  Remove the 4 screws from the casing that the filter sits in to get better access to remove the dirt and lint.  You'll have to stick your head in the dryer to see them all.  The filter sits flush to perfection now.  No more ruined clothes!