I'm so annoyed at my self. I backed into a fence post this afternoon. What makes matters worse is I have parking sensors, the problem was I was going too fast and thought to myself 'I don't need to look back, the sensors will tell me when I'm close to the wall'.....I'm such an idiot. Two lines of scratches on the back bumper. Anything I can do? I've tried scratch X which improved it a little but wasn't exactly sure how long I should spend rubbing the stuff in.