Hi
You can't take the inside lenses out of the unit without splitting the headlight, crap job, but doable, done it once with a mate on 06 A6.
It is possible to clean the lens from the inside but that is bumper off job to get the headlights out.
very tricky tho as not much room in there, and I mean very little.
Ideally you could post some photos for better advice, some from distance with lights on and without, some close up ones with lights off so we can make a better judgment before giving best advice.
I'm scared to even thing how much are new lights from the dealer, but I will have to look through all my links to find the supplier I found some time ago, 500-750 per unit without the control gear, which you have.
No point to buy the halogen ones of course.
If this is just the outside lens then that can be polished off and recover almost 100% clarity, but at the minute we dont know if its the bulbs or outside lenses which causes the issue.
Polishing will involve wet sand paper, the cutting compound and then buffing, but it isn't a long process and not expensive.
Post some pictures and we will take it from there
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2006 D3 S8 5.2 V10
Ceramic Brakes, Bang&Olufsen, DTV, DAB, Rear Camera, BT, TPMS, Soft Close, Auto Boot, AMI , 4 Zone AC, Home Link, All Electric Blinds, Fingerprint, Ski Hatch, Black Extended Leather, Heated Sport Seats, Alacantra, Carbon Trim inc Aluminium Pack 2.
2015 A3 S line 1.4 TFSI - for the missus to keep her away from my car.
Standard S-line equipment, no extras.
2006 D3 A8 3.7 V8 - SOLD but not forgotten