I recommend a wonderful product called Micro-Mesh. They sell a "Scratch Removal" kit for acrylic aircraft windshields and windows. There are a series of abrasive cloths that you step through until you have a crystal clear finish.
I have used this product for polishing acrylic, aluminum and various carving stone. It is very easy to use. They have an effective process and it doesn't take a lot of elbow grease or time. A Bonneville headlight would take about an hour if it were completely foggy or had gotten some solvent on it.
I always have a kit available for general purposes. I get it for around $20 at Aircraft Spruce & Specialty.
Part number 09-24700
2001 Bonneville SE - Dark Bronzemist Metallic - Mods: 180* thermostat, iPod adapter, Digital OnStar Upgrade
Planned Audio System upgrades: Front & Rear 7 Band Equalizer, Amps, Hands Free Bluetooth Cell Phone kit
Planned mods: Front PEM, Ported LIM, Ported Heads, ZZP SR Rockers, Aluminum Gaskets & Reprogram PCM