m38 air cleaner assembly

[eagle64]

well as I'm striping down the m38 for cleaning and paint I took the air cleaner assembly off. I opened the bottom pan, and turned the wing nut and everything is stuck tight.
if must have been many years sense anyone opened it up. there is black tar like substance stuck to the bottom pan, I think it was oil at one time.
but nothing else is moving. I put it in a pail with parts cleaner hoping this will loosen things up.
has anyone else run into this and ideas on how to fix it?

those darn little screws are a real pain to remove. and some I'm not getting out. other than hat I hope to remove the tub this next week.
thank everyone for the past information it sure has helped.
steve I added 2 photos album on page 15 under eaglemn, photos 23 and 24

[BullRun]

Sounds like sludge. I would just let it soak and eventually it will probably loosen up.

[oilleaker1]

The inner cartridge of wire mesh is a tight fit. If rusted a little, try gently tapping the outside of the air filter with a soft wood block. It might flex enough to break loose. Don't make any dents though. John