The headlight lens on my Acura RSX gets foggy being an old car. I purchased Meguiar’s Headlight Restoration Kit based on good online reviews. Think I picked it up at Walmart in the US though it is available at Canadian Tire and Amazon as well. The kit comes with a buffing pad you attach to your drill, polishing cloth and polishing paste. It is pretty easy and quick to use and has excellent results. I do need to repolish every year though.
Update: Further research indicates the headlight get yellow because of UV and that the factory installed clear coat has worn off. There are multiple youtube videos on how to apply a clear coat to your lens so you don’t have to constantly restore it. Will be a project for the summer.