Also, plenty of fungus and gunkus to clean up to brighten the whole assembly. It's strange, almost every screw on this entire camera is loose. Is that common on Medalists from some strange Kodak magic?
I sold an Autocord TLR to someone local. A few months later she called me up to say that every screw was loose. Weird. So I took it in and tightened everything up. When we met up for her to get it back, I asked if she rode a motorcycle or in helicopters. No, she used the camera at a local night club. At the front of the stage shooting bands. The night club has a sound system designed by Ray Dolby himself, some of the cleanest bass you will ever hear. So the bass speakers were simply vibrating the screws loose. I immediately took the camera back, stripped it down again, and added loctite to every screw.
A few months later I got another call from her...
Well, good luck with the rangefinder. Acetone helps dissolve some of the really hard spots, but don't rub the paint with it. And pretty well every piece except the center two triangle prism assembly is adjustable in at least two different dimensions. The back surface of the main triangle where it sits against the erecting prism is the usual problem spot to clean and leads to the main crisp dark spots. There are a few adjustments not discussed in the repair manuals. The erecting prism handles much of the up/down division and the tilt, so as the final move it is worth playing with a lot. Sometimes its mounting block also needs to be loosened and adjusted so that seating it home puts it in the right spot. Move slowly and methodically.
Oh, be careful of he center triangle prisms. I've had them pop off of the mounting plate. Also had the top one break away. Remounting is not fun. And check the rear viewfinder element, upper part that you look through. If things look fuzzy and basic surface cleaning doesn't solve it, check for separation of the element itself from the glass plate it is mounted to.