Best way to clean/scratch polish a CD/DVD/SACD?

I have used the Nitty Gritty machine and some other items several years ago. What have you liked in cleaning discs and are any of the units that claim to repair scratched discs really do anything?

A little windex and a buffing wheel. Deeper scratches benefit from a small dab of regular Crest or similar toothpaste used like rubbing compound. It is very gentle. Keep the CD moving at all times so that you do not create heat in any one spot. Good Luck!
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I use "Plastic Cleaner" that I found at TAP Plastics. Spray on, wipe off and buff. They say you should always polish from center to edge. I'm sure ordinary car wax would work as well.
Griots Garage has a plastic polish and scratch remover that I have had good luck with. Also Novus products are good.