Duct and Vent
A lot of lint that makes it past the trap will end up the duct. You may have to call a professional to clean the duct from the dryer to outside vent if the buildup is severe. A good indication of when a professional is needed is a lot lint present at the outside vent. It is possible to tackle this task by yourself but you’ll need to buy a vent brush that matches your vent’s diameter and length.
Interior Dryer Cabinet
Although you shouldn’t get lint and dust on the inside of the dryer, it somehow always finds its way through all the barriers. To reach this area remove the access panel and clean out all the debris with a vacuum. Avoid contact with the electronics to prevent damaging the unit.
If you are looking to clean the dryer’s partner, check out this article on how to make a washer clean itself.