Our car three-way catalytic converter cleaner is carefully formulated with mineral oil and phosphate esters. Designed specifically for effectively removing carbon deposits from engines and restoring engine power. The usage method is extremely convenient: 1. Add this product to the fuel tank before refueling and then fill the tank up. 2. Vehicles that have not been cleaned for a long time may have black smoke in the exhaust during the initial cleaning stage. This is the result of a large amount of carbon deposits being removed. After that it enters the normal cleaning stage and the black smoke decreases and disappears. It is recommended to clean and maintain it once every 5000 kilometers or so. It is recommended to use a car that has not been cleaned for a long time twice in a row. And it helps to reduce vehicle emissions making driving more environmentally friendly.