In my experience (strictly with 240s now) the yellowing is on the outer surface. Over the past 25 years owning 240's I've polished the lenses a few times, stopping short of finding a UV coating to keep them clear. Spent hours with 3M paint compounding polishes, plastic restorers, and elbow grease. They look nice for a season, then they're dull again.





Then, I had a wiring harness problem under the left strut tower caused by a rodent. To effect a repair to be proud of, I needed to pull the harness all the way back from the horn, and to do that, remove the left headlight assembly. Oops, the plastic adjuster assembly crumbled when removing the lamp. I checked into getting a new one finding it only $100 for an aftermarket lamp assembly. The entire thing, lens and all. I got a pair of them. Dec. 2021.

Now, this photo I took today, Sept. 2024, almost 3 year later. It still looks brand new, clear as crystal. And no, the car is not garaged.



Makes the car look so much better. Best $200 I ever spent on transportation.


--
Art Benstein near Baltimore

"Middle age is when a narrow waist and a broad mind begin to change places." -E. Joseph Cossman