I used the Gliptone product that I bought from BavAuto during a sale. There is no sanding involved as it uses chemicals to peel off the oxidation. It also comes with a sealer. I did it this past January/February and loved the results with minimal effort. It is holding up great but the car sits in the garage at night and a parking garage during the day.
https://www.bavauto.com/bmw-headligh...on-kit-gt71647