Re: How to restore sanded and dirty back of neck to OEM finish?
if it is bare wood, you can tung oil finish it to help keep it from getting grime/finger cheese build up. I have used boiled linseed oil as well, but you want to keep the coats really thin, as the linseed oil can get tacky and turn amber with too many coats. As far as refinish goes i'd probably take it to someone who has an actual spray booth.
I saw on this form someone used simple green to clean their maple neck and fretboard. I have never tried that but have used tub'o towels to get gunk and buildup off of fretboards with great success.