You will need to start with 120 grit sandpaper - or possibly 240 if you want to be carefull. then work up the grades to about 1000 grit
give it a liberal coat of oil and leave it overnight, then wetsand the neck with the oil and 1000+ paper - probably going up to 1500. When i say wetsand i mean apply some oil to the paper/neck and keep it lubricated with that as you sand.
you will need to buff of the gunk every so often
once its done leave it overnight again and personaly i would apply a coat of wax the next day - apply and polish it with 0000 wire wool. Buff it out and reattach it!!!