This is part of what SHIFTING Into 4WD offers about staying clean, starting on page 66.  For the complete text and graphics, go here.

Actually, you don’t have to eat others’ dust all of the time! The first suggestion, which also plays a safety role, is just common sense. Don’t drive in the dust, and I understand why newcomers do. Some travelers are so afraid of getting lost they lock bumpers with the guy ahead. ... Clean rule one: Follow back a ways.

"A ways" is just far enough to be out of the grime, but occasionally in sight of your traveling companion just ahead and behind...

But dust alone is not your final close criteria. No dust in the rocks, huh? How about the rocks the gal ahead is kicking up? Follow too closely and you may end up with one in the windshield! ...

In general, follow back a ways and experience the wilderness, not recreate commuter chaos.

...Your flat, near-vertical rear window probably won’t catch mud balls, but it certainly adds a curve to the airflow. Airflow at the rear of a flat back-windowed SUV sets up things called eddy currents. These illogical little dust devils move dirt forward. The same goes for pickup trucks with camper shells. An open pass-through or rear window assures you of a dusty dash at day’s end. Keep those windows closed in all but the best of conditions.

I travel with my windows down much of the time. I like the smell and feel of the outdoors. But I never hesitate to hoist the shields when needed.

...My advice is to use your air conditioning 100 percent of the time. It really helps keep the inside of the vehicle clean. The trick lies in selecting the option that recirculates internal air. This is sometimes called "RECIRC," "MAX" or there may be a graphic that shows an arrow inside the vehicle.

The recirculate position does what it implies. It recirculates existing, clean, internal air and only brings in about 5 to 15% new, external, dirty air. In other modes such as "bi-level," "economy," "norm," "vent" or the external arrow graphic, you are introducing 85 to 95% "fresh," external, dirty air. That simply means more dirt, too! Further, recirculate pressurizes the inside and keeps the dirt from entering at less conspicuous points like the door bottom water drains.

But what about cold days? Your temperature control will heat the air-conditioned air just like heater air. Just move the temp lever to make you comfortable...

What most folks don’t know is that defrost automatically turns on the air conditioning. This dehumidifies the air blown onto the windshield (removes the moisture), which means no more fog. Air conditioning is designed to deliver air at any temperature. Try MAX with the windows up, at any temperature. It works wonders with regard to staying clean.