Installing custom cabin air filter
Loosen the nut but do not take it all the way off. Pry off the wipers with some channel locks.
Pull out the center of these little guys and pull the entire thing out.
The weatherstripping just pulls off and the plastic piece comes off.
I picked up some filter material for Window Air conditioner units at walmart. It wont do as good as charcoal filters, but it gets all the dust out of the air.