i would very lightly sand it. You will get more input and from experienced builders if you pose this question on the rodbuilding board. Cleaning cork is fairly common. Unfortunately some of the rodbuilder are stuck in that forum. Trapped in there.
Vessel: 17' Boston Whaler Montauk.... "Chocolate Bass"
Location: La Mesa
Job:Biotech Engineer
Bio: Calico's, Sandies, and Spotteds
Re: Cork grips???
I would mix a "little" bleach with dish soap, and use a tooth brush to clean it up. I've done it on several of my rods and it seems to work great. I've also taken to adding X-rap to the lower portions of my cork rods (where my hands touch) so that i don't have to clean them anymore. It kind of looks cool...