I have 2 custom rods that have custom grips on them. One is regular cork the other is burl cork. Both grips are a little too large. I would like to sand them both down. I started doing that with the burl cork and I have developed a ruff surface that I can't seem to smooth out. I used 150 - 220 - 300 sand paper. I also am having trouble getting the shape of it to fit my hand. Haven't started on th regular cork and now I am afraid to. Any suggestions?