You are spending a bunch of time for no reason. Sounds like the motor is basically garbage. Brake parts cleaner is not good for bearings or electronics. You could spend a bunch of time and money trying to get this unknown motor to work, only to have it burn up when you use it. It could very well burn out your esc too.

Also, you can post pictures directly to your posts by clicking the paper clip above where you type your post. What came off the solder post was probably a glob of solder with wire bits from old wires.