Lens restoration disappointment

[AV8R4AA]

I had my drivers side headlight assembly completely removed.
I did it because I have the ABS module out for overhaul.

I bought the 3M kit. Used my trusty drill, read the directions and went to work.
The kit works very well, the lenses came out great!

After about an hour buffing and grinding and polishing I was done!
My disappointment was the INSIDE of the lens is dusty and has water marks.
I have the headlights that don't bake. Mine are sealed (although poorly)
with a silicone product. I would REALLY like to get to the insides of this headlight
assembly. Most guys here say that it's a bearcat to split the cases, and they wouldn't do it again.
Any ideas on how to clean the backside of the lens?