Judge

I'm understanding that my starter is bad but the solenoid is still good, but actually no one is answering my post below asking about that situation. (removed - the starter motor kicks, but no twist.)

The starter went bad after the typical ignition switch problem, of the key not turning back, so that when I drove, the car motor was turning the starter motor.

It was for a short distance of less than a mile.

If I try to open the starter motor with the idea of fixing, what would I look for? Any hope?

BigMouse

Cooked armature winding (most likely. Not repairable)
Cooked field winding (not repairable)
Brushes (not likely. Replaceable if you can find replacements)

You'd need a growler and a 110v test light to check them. In other words, you're better off buying a new one. Thats what I did. Mine broke for the same reason. Didn't pull it apart as I needed it intact to get my core charge back.