They work ok. Best thing to do is to wet sand the head lights with sand paper with finer and finer levels of sand paper and spray a few layers of clear coat on the head light after. The other option is buying new after market headlights depending on the vehicle could be relatively cheap. Also if you use any kind if power sander be very careful you dont burn a hole into the plastic. You would be surprised at how fast that happens.
Yea, you have to sand off the nasty yellow shit and buff them back clear, then put clear back on them, depending on the car the aftermarket headlamps are not a bad way to go like @Ballbuster1 one said, once they yellow they will do it again
It's a 2004 with 38,000 miles that just needs a little tlc. Not my daily driver. Don't be a douche. Thanks to everyone else for your replies. Aftermarket is not an option because
it's not a common make even though it's a GM.