Frozen micrometer

[Roadracer_Al]

May I suggest, as a last resort, my favorite carburetor cleaning method: dissolve a fair bit of laundry detergent into a pot of boiling water, and simmer whatever it is you're trying to clean for 1/2 to 1 hour. This will dissolve any hardened grease, loosen any baked on filth, and remove any ancient varnish from a carb, I imagine it will do the same for a mic. It might even remove the paint.