How should I properly clean my Audi A5's headlights?

I noticed that my Audi A5's headlights are getting foggy and dull. What is the best method to clean them and restore their brightness?

One way to clean foggy headlights is to use toothpaste as a mild abrasive. Apply a small amount of toothpaste onto a damp cloth and gently rub it onto the headlights in a circular motion. Rinse off with water and dry with a clean cloth. Repeat if necessary until the headlights are clear.

Another method is to use a headlight restoration kit, which can be purchased at most auto parts stores. These kits usually include a special polish and a sealant to protect the headlights from future fogging.