Headlamp cleaning

[tonto555]

Hey all, Im in the process of preparing my van for respray, after removing the headlights I noticed some spotting on the reflective surface. Any advice on cleaning this without scratching it?
Also how do I remove this piece from inside the casing?
it seems to only be held by the adjusting screws, I dont want to force anything and break it.

[tonto555]

Advised against cleaning and ordered new part.
As new part was ordered I decided to attempt cleaning, heres the result.

[adamuk]

Blerugh.. not pretty.

[tonto555]

not pretty at all, didnt rub too hard either, just used a regular spray on glass cleaner and soft cloth.