First of all observe the scratch and its seriousness. Once you make sure that your car’s body got real scratch not a mark then you will be busy in preparing the car body for repairing. Clean the scratched area of car body thoroughly and level it down by sanding. Use gentle laundry detergent or shampoo for car wash. Take a fine-grained sandpaper to level the smashed area.....http://www.repairingforum.com/car-repairs/tips-to-repair-a-scratch-on-car.html