4. Window Cleaner or Polish
Ingredients :
Window cleaner or polish
Instructions :
Apply a few drops of cleaner to a clean cloth or old toothbrush.
Rub the headlights in circular motions.
Wipe off any leftovers with a damp cloth.
Tip : Make sure the cleaning product does not contain ammonia to avoid damaging the plastic of the headlights.

5. Isopropyl Alcohol
Ingredients :
Alcohol (isopropyl or other)
Instructions :
Soak a cloth with alcohol.
Gently rub the headlights.
Rinse with water and let dry.
Alcohol is an excellent degreaser that dissolves oils and other dirt on headlights.

6. Sandpaper (Sanding)
Ingredients :
2000-3000 grit sandpaper
One of the products mentioned above (alcohol, vinegar, etc.)
Instructions :
Lightly sand the headlights with the sandpaper.
Then clean with one of the previous solutions.
Repeat if necessary.
Caution : Be careful and do not force too much, the goal is to smooth, not scratch the surface.