It depends how deep the scratch is your talking about. Is it through the paint or not that kind of thing. If it is through the paint, or deep enough you can pick at it with your fingernail, then I would get a duplicolor 2 in 1 pen. They match well, and the pen end is great for those.
If its not, then I would try newfinish scratch remover, followed by a very light rubbing compound, glaze, and wax.