We get many typewriters that have surface rust. This is OK as long as rust or other corrosion has not invaded inner workings. This is an Underwood typewriter that came to us with a lot of rust. When I put it in the queue, I immediately doused it with penetrating oil to give my customer a half chance I could save it. The rusted screw tops and other minor corrosion didn’t worry me as an Underwood can stand one heck of a litany of abuse and still come out running.
The real issue with this nice machine is the rust in the segment. Several keys are just plain seized and the pivot rod that runs the length of the segment is rusted in place. If I can get the type bars removed and the segment out of the machine I have a good chance of getting this Underwood typing again.
Oh, if I was not crystal clear; keep your typewriter in the house warm and dry. No garage, no attic, no trunk of the car. Rant over, thanks for listening.