ISO 5011 filtration tests have proven that cotton-gauze air filters do a great job filtering our dirt and debris. However, when they get dirty they can clog up and limit air flow. This is one reason why you should clean your air filter with Injen?s filter cleaner kit. Our air filter cleaning kit contains Injen?s filter cleaner that loosens and removes trapped dirt and debris deep inside the media. Injen?s proprietary air filter oil contains a red dye to easily see where the oil has wicked into the filter media, eliminating the common mistake of over oiling the filter. When used correctly, Injen?s filter cleaner kit can maintain the life and performance of your Injen high-flow air filter.