The clear coat that protects your car is porous and filled with micro-ridges similar to your skin. From a distance your clear coat appears flat but when you look at it through a microscope you see that it has ridges. Contamination can easily become lodged between these areas and reduce the optical clarity of your paint, thus creating a dull shine. Spray a clay lube on the surface and glide the Clay Magic Medium Grade Clay Bar over these areas and you will pull out contaminates. This is similar to the process of exfoliating your skin. Thus you gain back a clean clear coat that is very smooth to the touch and contaminant free. An additional benefit to prepping your paint with a clay bar is that waxes and sealants adhere to smooth and contaminant free paint much better. This means that the wax or sealant will protect and shine for longer. We recommend cutting this extra large bar into 4 to 5 pieces so you get multiple fresh uses from one large 200 gram bar. Store the bar in this container to protect it from contamination in the air in-between details. This medium grade clay bar is designed for vehicles that need extra care and are heavily contaminated. The medium grade bar is best suited for removing extremely stubborn build ups like paint over spray, sap, heavy tar build ups, etc. Get the maximum shine and results from your detail by starting off with the Clay Magic Medium Grade Clay Bar.