Restoring AC

Pull the inlet line off the expansion valve use a dental pick to pull those little cone shaped screens out. Should be 5 or 6 stacked togeteher. Seperate them, clean them , reinstall.
There is plenty of info on the web about the RV2 compressor including its crankcase oil level.

I have another concern which I forgot to mention. How hard will it be to convert to the updated freon? Or, is there anyway possible I can get a hold of some old freon?