VIDEO - Do It Yourself Headlight Lens Polishing
This video from Sylvania shows how the do-it-yourselfer can take a bit of time and their polishing kit and restore the clarity to plastic headlight lenses. Milky or badly yellowed lenses turn crystal clear again. This restores properly focused light that helps you see effectively and eliminate glare for other drivers, likely far less expensively than buying new lenses!
Consumer Reports says that these restoration kits do work and are a better value than replacing your headlights. Their buying guide for March 2021 recommends the Sylvania headlight restoration kit which you should be able to purchase locally for about $40.00.
According to the guide:
It involves a total of six steps, including progressively finer grades of emery paper, rinsing, and a final coat of UV-blocking polymer coating that is best applied with rubber gloves and in a well-ventilated area. Applied entirely by hand, it reduces the risk of damage to surrounding paint. The Sylvania sanding papers are larger than those included with some other products, making them easier to use, but the best results do require some effort.