I read about a fix for this on another forum, havent tried it myself but here's how it went. (My thoughts are: try it yourself. If it doesn't turn out, you'll just have to take it to a rod builder which is what you would have had to do if you didn't try it yourself.)
carefully cut out the damaged portion of the cork. This is the most dangerous part as you could damage the blank if you're not careful. I would start at the middle and pull out chunks of cork with a pliers. Work your way towards the ends of the damaged area and then cut the edges of the cork clean and straight. Sand off the remaining cork and epoxy from the exposed section of the blank
You'll need to get your cork rings you're using to fix and measure to see how long a section you want to replace. In a perfect world you could cut the damaged part of the handle at the glue lines between the rings. This might work, but if the new rings aren't exactly the same thickness as the old rings your length will be off. So you may have to cut one end of the repair section in the middle of a ring which could be a pain.
Turn the new rings down until they are slightly over-sized. Then ream them until the holes in the center of the ring will fit over the exposed portion of blank. You can't slide them on like you would with a new build so you will just have to measure. If anything you want them a little big. If they're too small the rest of the repair won't go well.
So now the new rings should stack up to the same length as the area that's been stripped. The holes should fit over the blank and the outside diameters should be ~1/16th or more bigger than the cork adjacent to the repair area.
Then next step is to pick the ugliest side of each ring and cut a slit between the hole and the outside. You're not cutting the ring in half just cutting through one wall of the doughnut.
Boil the cork. I don't remember how long the original poster said to do this, but I would think a half hour to an hour would be enough
. After boiling, the cork will be flexible enough to carefully slide the blank through the slit. You'll need to have epoxy on the blank and some on the faces of the slit as well. Wrap the new cork very tightly with saran wrap to compress the slit closed tightly until the epoxy sets up.
So now the new cork is on the blank, but it's a little taller than the rest of the grip. Sand carefully until it's flush. Enjoy.
If you screw the pooch, you're out the cork and epoxy you bought (cork can be expensive), but, unless you killed the blank, professional repair won't be any more expensive than if you'd have taken it there first. If you do mess up the blank while stripping the cork, it will be under the grip where it can be repaired and hidden.
You're call. If you're a general fix it sort of person and take your time, I don't think it will be a huge deal. The only thing I'm doubtful of is amount of time to boil the cork. I also am wondering about gluing up the cork after boiling. I don't think the epoxy will bond if the cork's wet. I'll have to find that post again to confirm these two details.
EDIT: Found it http://www.rodbuildingforum.com/index.p ... place+cork