Keep your car smelling fresh and clean with a homemade air freshener. Fill a large tea strainer with either charcoal (the kind for the grill) or dried lavender. Charcoal is a natural deodorizer, so it will absorb foul fragrances. When it's left in a warm car, lavender will perfume the air with a soothing and pleasing scent. This is a healthy alternative to chemical-based, artificial car fresheners.