A clay bar can be effective in removing tar and other contaminants from your car's surface. The clay bar is a detailing tool used in the process of clay bar detailing, where it is gently rubbed across the surface of the vehicle. This helps to lift and remove contaminants like tar, road grime, and other pollutants that can adhere to the paint. It's important to use a lubricant, such as a detailing spray, while using the clay bar to prevent scratching and ensure smooth gliding. Regular clay bar detailing can contribute to maintaining the cleanliness and smoothness of your car's paint finish.