This powdered detergent is perfect for dissolving the filter oil from most foam air filters. Specifically recommended by ITG, but also ideal for Pipercross filters as well as our Universal Air Filter Foam. One 16-ounce bottle is enough for several cleanings (up to 8, depending on filter size). Cleaned filters must be re-treated with our Universal Foam Air Filter Oil (Part No. 3895, sold separately) before use.