I start with the parts in a plastic bin:
|Parts ready to be de-rusted|
After soaking a couple of days, the parts are ready to be scrubbed down.
Next I take an old toothbrush and scrub off the remaining black stuff from the parts. A sink with running water is the best place for this.
|The cleaned up parts|
The balance wheel's rust has been removed, but the areas that were rusty have still lost their paint. I suspect the whole wheel will need to be stripped and repainted (and the pitted places on the rim smoothed out).
The most improvement comes in the chromed external parts.
This is a now a faceplate that would dress up a sewing machine.