Step 1
Remove the air filter from your vehicle, and rinse it with water from a garden hose. Hold the filter in one hand, and spray from top to bottom to remove built-up dirt and grime.
Step 2
Pour 1 cup baking soda into a small bowl, and add enough water from the hose to make a thick paste. Baking soda is mildly abrasive, and can scrub off ground-in grime from the folds in the filter without damaging the filter’s fragile material.
Step 3
Rub the baking soda paste over the surfaces of the filter, working it into the folds and crevasses with your fingertips. Set the filter in a sunny location and let the paste soak into the filter for 15 minutes.
Step 4
Rinse the baking soda paste from the filter with the hose, rubbing the folds gently with your fingers. Run clean water over every surface of the filter until the water runs clear and no traces of the white paste remain on the fabric. Let the filter air-dry.