Pick out any loose fiber tangled around anything and clean off your drums.
Oil moving parts with spinning wheel oil, machine oil.
Make sure that everything is dust, screws tightened, and belts where they should be.
Use Howards feed and wax, see if anything is getting warped/etc.
I Have also read an article that suggests sanding microscopic burrs from the teeth of your drum carder before you begin using it. I intend to do so before starting to use my new drum carder.