ka43 said..
I posted the whole process on how to do it. Have a search.
Anyway, sports tape under the boom grip works great. Do the hard work and get rid of the old boom grip.
I agree, especially for carbon booms that keep their strength over time. Sometimes you're lucky and the grip comes off pretty easy, other times it takes a long time. It gets messy when using solvents so try a dry rip, with some help with a sharp knife. Glueing the new grip on the boom is the easy and rewarding part. I tend to use new original grip as you feel like having a complete new boom for just 50,- Just make sure it is worth the repair and it can still last a while.