The brushes look like they should be replaced, but the rest of it looks like it should clean up pretty well with some light solvent like WD40 and a toothbrush, then later with some electronic parts cleaner.

I would also recommend investigating the condition of the gearbox, which has not been disassembled yet (based on your pics.)

Oh yeah, and as far as winch cable, I highly recommend synthetic rather than steel cable. Synthetic is much lighter, safer, and easier to handle.