What matches a car that's just been washed and waxed? Headlights that are sparkling from a recent defogging job. Over time, it's very common for headlights to become fogged and unattractive, and they don't illuminate the road most effectively. That's why you should use a few techniques to take off the scratches and grime that gives your headlights a cloudy appearance.
To remove scratches, you can try using sandpaper to buff them out. The general idea is to start with coarser sandpaper and move to finer grits. But you need to know what you're doing to avoid making it worse.
If you have a lot of grime on your headlights, you can also use an insect repellant that has Deet as one of the ingredients. But be careful. This type of insect repellant can also take the paint off your car, so you should put it on a rag and wipe carefully.