It's a common problem that eventually occurs to all Contours.
Any sort of plastic polish or mild scratch remover will work fine. Some people have good luck with Toothpaste, and seeing as you caught the problem early, that might work for you. I bought my 'Tour used some months ago and now regularly buff on some plastic polish. It took a long time at first, but now I just do it for a few minutes when I wash the car to maintain the clarity. I picked it up at PepBoys; it's made to remove minor plastic scratches and clean the rear windows in soft-top convertibles.
For more severe problems, some very mild grit sandpaper can do the trick, but I don't think you need to do that.
