A clay bar is a detailing tool used to remove contaminants from the surface of a vehicle's paint that regular washing cannot eliminate. It effectively lifts embedded particles such as industrial fallout, brake dust, tree sap, and tar, leaving the paint smooth and clean. Using a clay bar helps prepare the surface for polishing and waxing by ensuring it is free of impurities, enhancing the overall finish and allowing protective products to adhere better. Proper use involves lubricating the surface with a detailing spray to prevent scratching while gently gliding the clay bar over the paint.