How to clean lenses inside Anschütz Adjustable Front Iris?

Hey guys.

I have this adjustable front aperture from Anschütz.


It’s constructed so that there are two internal lenses with the iris built between holes cut in both lenses.

I need to figure out some way to clean the inner sides of these lenses. The outer facing sides are no problem. But after months of outdoor shooting, they are getting a bit foggy on the inside.

Any ideas? Previous experience?

Thanks in advance!

-Delta