Most cork now a days comes with a bunch of filler in the voids as well as a very light skim coat over the grip. It is very thin but gives the illusion you have much nicer cork than you really do. Put that grip on a mandrel and chuck it in a drill. Choose any sandpaper you would like and go lightly until the cork feels like you want it to. If you get real aggressive with it you will pull chunks of filler out out of the voids.Does anyone know where i can find a rougher cork handle? The last 3 I've used were sourced from mudhole and I'm not in love with the smooth finish of the cork. I prefer a rougher more textured finish (no synthetics either). What I prefer is unusually found on older fly rods. Does age have something to do with it maybe?
If you have a power wrapper you can do this with factory rods as well. I just retouched some cork on a Loomis CC Pro1 where he did not like the asymmetrical shape of the grip. Chucked it in the power wrapper and turned it down a little at a time to suit his hand and grip. Much better now.