As headlights age UV from the sun and excessive heat from the headlight globes slowly wear down your headlights exterior surface coating. As this happens your lights become yellow and cloudy and the brightness of your headlights at night greatly diminish.
There are lots of products on the market claiming they can quickly reverse this process permanently by rubbing wipes or polishes on the surface of the lights until they look new. Some products will give short-term results but none will give you a permanent solution.
The only way to permanently reverse the damage is to completely sand the surface of the headlight. Once sanded flat we paint the headlights with a protective layer of 2k clear so that headlights look like new and have the best possible UV protection preventing further damage.