After serious thinking Jules Richardson wrote :

We've got about 210,000mi on the car at the moment, and the clear plastic
lenses for the headlights are getting decidedly yellowed/murky after so
long - they're getting to the point where taping candles to the front of
the vehicle might be more effective

I keep seeing ads for some sort of restorative polish stuff (which may
well be snake oil) - but it got me wondering if a DIY concoction might be
worth a try - e.g. I've found in the past that combinations of toothpaste
and baking powder work very well for removing scratches from CDs, for
instance, but I wondered if anyone can recommend any other home
remedies? :-)

If you wet them and the murk improves, then all they need is a mildly
abrasive polish - Brasso, T-cut, Autosol or any similar mild abrasive
will work fine.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk