Really depends how bad they are. I have used a white filler polish for some scratches, a buffing compound for others, sometimes if the chip is small I use a toothpick and touch up paint, if larger I use a paint brush. For a couple of really bad scuffs on the cod section I decided to sand and repaint the whole piece.
Sometimes you will find it is better to paint a whole section rather than trying to touch up, especially when using a spray can, you will normally find drying on the outside areas that you are trying to touch up and it really doesn't match well.