Had a day off work so thought I'd do a D.I.Y about restoring the headlights, here it goes:
1.) This is how the headlights looked first, dirty and rough and starting to turn into piss coloured lights.
2.) Grab some fine waterproof sand paper (I used 2500 and 1500)
3.) Splash some water on the headlights then wet the sand paper and start sanding. (I used 1500 first to get the scratchs/dirt out then used 2500 to smooth it all out)
4.) After sanding the whole head light, rinse it with water so all the dirt comes off then dry it. (Should look like this)
5.) For myself I've used ScratchX for couple years now and works a treat but there are other products out there you can use. Put the ScratchX (Product) onto the headlights and rub it around.
6.) Get a buffer (I used the one you plug into the electric screwdriver) and start buffing the lights.
7.) End result? Smooth and silky, no dirt and colour has been brought back to life.
8.) Repeat the steps for the other headlight.
And for 3 series BMW's like my daily, its pretty much just unclip the headlight plastic clear cover, go to the sink and wash it inside out and dry it then clip back in.
Cheers
John