If your car has that damp, musty odor that you can seem to get rid of no matter how much ventilation you give it, try this: remove the cap from a bottle of white vinegar and drop in a cinnamon stick. Place securely in the cup holder, close the car windows, and leave overnight. The vinegar will help absorb the musty smell while the cinnamon will give off a light, warm scent. In the morning, remove the bottle and open the windows. The odor should be gone.