If contamination is present on the wheels or the painted body panels, there’s a chemical reaction that takes place when 3D BDX chemically dissolves the contamination. The visual appearance of this process is the 3D BDX (and the dissolved contamination), turn a dark, purple red color. This is a sign contamination is in fact present. The good news is by dissolving the contamination so that it can be flushed off with rinse water, you have stopped any corrosion taking place on the finish of your car’s wheels or on your car’s paint. Considering how thin modern car paint is – it’s important to keep it clean and contamination-free. After washing the car, you can move onto the next step knowing your car’s wheels and paint are clean and free from any chemical contamination. What if I don’t see any color changing effect? After spraying your car’s wheels or any of your car’s body panels, if you do not see any color changing taking place in the spray on the surface, this is even better news . It means there is no contamination and more important – this means there was no corrosion taking place on the finish of your car’s wheels or on the exterior paint. Believe it or not, even though everyone loves to see the color-changing effect, also called the bleeding-effect , it’s better for your wheels and paint to see nothing at all. And now you have the confidence to move onto the next step knowing your car’s wheels and paint are clean and free from any chemical contamination.