Our car cleaner is carefully formulated with mineral oil and phosphate esters. It is specially designed to effectively reduce engine vibration. The usage method is extremely convenient: 1. Add this product to the fuel tank before refueling, and then fill the tank completely. 2. For vehicles that haven't been cleaned for a long time, there may be black smoke in the exhaust at the beginning of the cleaning process. This is the result of a large amount of carbon deposits being washed away. After entering the normal cleaning stage, the black smoke will decrease and disappear. 3. It is recommended to perform cleaning and maintenance approximately every 5,000 kilometers. For vehicles that haven't been cleaned for a long time, it is recommended to use it twice consecutively. 4. Please do not clean in the following situations: if the three-way catalytic converter is damaged due to high temperature or lead poisoning, if the three-way catalytic converter is severely clogged, if the engine has oil leakage, such situations need to be treated before use. Moreover, it can decompose deposits and clean the entire fuel system through the flow of fuel.