These 3 products are very easy to use... ; How to stop diesel exhaust smoke is as simple as... Adding the CRD Fuel Enhancer and the FTC Decarbonizer directly into the fuel tank when refuelling and adding the Flushing Oil Concentrate to the Engine oil. CRD Fuel Enhancer ; Is added directly to the fuel tank Cleans injectors and restores spray patterns Minimizes injector rattles Reduces diesel smoke Flushing Oil Concentrate Is added directly into the vehicles engine oil Removes engine oil sludge Frees oil rings and restores compression Reduces oil use ; and exhaust smoke FTC Decarbonizer Is added directly into the fuel tank Removes carbon Cleans Turbo's and DPF filters Restores power and stops smoke Packages available for petrol engines ...