Clear windshield fog: Heavy fog on your windshield can make winter driving dangerous. To clear the exterior, turn up your defroster and only drive when it’s clear. Moisture can build up inside the car and fog up the windshield’s interior, so remove any water (from winter mats boots), crank the heat, then slightly crack your window to let any moisture out. You can also put some kitty litter into a sock and place it under a seat—the litter absorbs the moisture and helps keep your windows clear.