Binocular Restoration Attempt
So I gambled on an old pair of wide-angle binoculars. Theoretically these were beautiful old Jason Statesman binoculars, 7x50 with an 11˚ field of view / 77˚ apparent, which is an absurd FOV by even modern standards. I picked them up for $30, and quickly discovered why.
Mechanically they're actually overall in decent shape. They were dropped at some point and suffered a small scallop chip at the edge of one of the prisms, but it's hardly noticeable in the image. These could potentially be restored to have a great picture quality, the only real problem is the grease.
All that old damping grease has broken down into basically glue, so nothing turns or moves how it should. The solution is concentrated isopropyl alcohol, which annoyingly is also a solvent for the glue holding together any cemented lenses, and I presume probably not great for the faux leather skin.
To clean these, I'm guessing the right path forward is complete disassembly. The prisms will have to come out regardless due to some fungus growing on one lens, and the eyepieces are all contaminated with broken down grease and I think 40 years of the previous owner's smoking habit.
UPDATE 1:
Disassembly has gone dramatically better than expected. With a little sweat and blood I've managed to get the prism covers off both sides, the prisms removed, and prepped for cleaning. Cleaning these prisms should be pretty easy i think, and cleaning the objectives in-situ should be super straightforward.
What's actually going to kill me is the eyepieces, or more specifically the eyecups, which are filthy and, on the right side, I think are holding the diopter together, which is super sticky and gross and will contaminate everything if I don't disassemble and clean it.
The eyecups are aluminum, kept in place with a reverse-threaded locking ring that likely needs a spanner to come off properly. The metal is super soft so I really don't want to try to just hack my way through opening this piece. I'll probably end up finding / buying a cheap lens spanner wrench. And, if it turns out that's not how you remove the diopter, I will cry. I have removed the entire optical stack from the middle of this eyepiece, and yet the diopter remains captive, not a set screw in sight.