Frontlights glass cleaning

Hi folks!

Finally again one question from a SVX-Driver from Switzerland . Following problem (attention "Swiss english"):

On the inside of the left frontlight-glass it has a light grey coat. It doesn't disturb much when I drive in the night, but it doesn't look good, special because the right one is clear.

I ask my Subaru dealer, if they can clean the glass from the inside. They say no chance, only possibility is to change the front light (what is very expencive). I think one way to try is to remove the bulps and try to clean the glass through this opening.

I want try to sprinkle inside special breakcleaner (MolySlip) who doesn't damage plastic (so the frontlight glass too not). Or have somebody a better idea?

Kusi