Ok, apparently the person who owned my car before me decided it would be a good idea to throw some touch-up paint on top of some rust. It's all bubbly and it's chipping off. How can I fix it? Can I just sand it down and repaint it? I know I won;t be able to get it to look like new but I just want it to look better than it does now. The spot is about an inch wide and half an inch high. Thanks!