Brasso!
Whoever told you to use Brasso was correct- it's a great plastic polish. In fact, I think it works better than Novus, which is a very expensive, HTF plastic polish made for the job. Brasso also has the advantage of being available in every hardware store and most grocery stores.
I would add one thing to what Tom has said here. If you want a really nice final shine, as well as some anti-static protection, Favor High Shine furniture polish works really well. It's next to the Pledge in the furniture polish section of the grocer's. When using Favor High Shine, be sure to buff well with a very soft cloth, to remove all excess.
I use Brasso on the headlight lenses of my Volvo 240- these plastic lenses have a tendency to yellow and cloud up. Replacements cost a fortune. With Brasso, my lenses look new, on the cheap.