The rust remover product was purchased at a farm store in the automotive department. I think the name had 'blaster' in it, but not sure. Anyway, I put the old bobbin case in a paper cup and sprayed it with the product, enough to soak it. It seems to have taken off some of the rust, but there are a few places that still need some work.
I wanted to use mineral spirits on the presser bar and needle bar to get the gunk off, however I could not get the lid off the can of mineral spirits! I used a bit of the rust remover on a q-tip and it helped get some of it off, but I need that can of mineral spirits opened!
I left the can on the kitchen table with a small jar and lid. I'm hoping when Ev gets up he will open it for me and pour some in the jar.