Over the last few days I have been getting a lot done. Almost 100% of the rust is gone after soaking it for a few days, and in the meantime I've continued with my restoration. First up, I've started taking a small screwdriver and removing the spring bits that are still stuck inside the keycaps. I got a batch of about 30 done yesterday and put them threw about 20 minutes of ultrasonic cleaning (my cleaner actually died, so hopefully it still works after letting it sit for awhile). They are looking much better and the water turned a gross yellowish-orange color. I have also started working on the hammers and have been removing any remaining spring bits from those as well. I've currently got about half of them done and I'll be putting the new springs on soon.
The PCB is looking really good considering how it did a few days ago. There is a bit of damage around the sides of it, so hopefully it doesn't affect the circuits at all. All I did was soak it in my solution and everything is looking good as new. The backplate had a weird grayish patina on it that was a bit sticky. I have no idea what it was, but I sanded it down and tried to remove as much of it as I could. The plastic separator also has that weird gray gunk on it, so I may make a new one if necessary instead of trying to remove it all. I lightly sanded the barrel plate and sprayed the antique nickel Rustoleum on it alongside the backplate. It looks really good in my opinion, I'm not sure if it will even need more than one coat. The derusting formula managed to remove the staining from the case and it looks great now!
Almost everything is starting to come together at this point and I am starting to see the light at the end of the tunnel so to speak. My only hope is that the keyboard actually works after all of the work that I've put into it.