A few weeks ago at a junkyard, an older guy with a European accent and I were talking; he mentioned that one way to clean yellowed headlights was to clean them with brake fluid. He took one, dipped his finger in the brake fluid reservoir, and rubbed a light film on the lens. He then wiped it off, polishing it up, admonishing me to wipe the lens clean immediately, as the brake fluid will begin to become sticky, which is the end of the lens. I have to say, it seemed to work, though it didn't make the light 'like new'.

I can't say that I recommend this, nor have I tried it, because I'm overly cautious about poisonous fluids in general, and misuse of poisonous fluids specifically. However, I was wondering if anyone else had heard of this, or come across this, or tried this here.

Best,

Lanval