that's typically on the inside of the lens. When you have a seal break (somewhere along the silicone gel lining or a headlight gasket), moisture + air + heat + cold + heat + air + moisture + air = that.


You can seperate the lens from the housing via oven bake method. When you get the lens seperated, you'll need to use some rubbing compound and maybe a wet sand.


easiest, best looking method? just get new parts on eBay.