Now I know this is crazy and many would not try this but if you try enough dumb things you stumble across some that works. I acquired an old Argus with a frozen shutter that did not respond to lubrication with naptha. The common wisdom is a CLA which was not worth it in this case. So I soaked the component in a naptha bath for 2 hours. Then liberally lubricated it with light mineral oil USP. Then put it back in the bath for 1 day occasionally swirling it and removing from bath and shaking it. After 24 hours it was partially working. 2 days later after the naptha evaporated it was working like a fine watch. perfectly smooth action and has been so for 2 months. I tried the same with 2 other similar configurations with the same success so far. I have not done this with plastic components yet (do not think advisable) but these results are amazing to me and I have not seen it suggested before. It is worth trying on a camera that would otherwise be conscripted to the junk pile. The time periods and mineral oil are arbitrary and what is crucial is not determined but I know this has worked.