Two picts below. I had just finished using my router and it is dusty. But it shows the circular clear plastic (PET) bottle deflector. Dust still gets in but it does not fall straight down into the motor.
Horizontal view of the PET deflector:

THIS pict gives a better view of the simple set up:
Horizontal view of the PET deflector:
THIS pict gives a better view of the simple set up:
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