Some time ago, a bulb exploded in hundreds of pieces inside of my headlight unit. The result was that the reflector and the glass was full of white dust/powder.
The question is: How do you clean the damn thing on the inside???
First I disassembled my headlight unit and I took the bulbs out. Then take a rag and put it inside the holes of the bulb with a screwdriver, just leave a piece outside so you can still pull it out afterwards. Rub the rag with the screwdriver against the glass until it’s clean.