Mine is about three weeks old, I just used a clean cloth with a bit of water.
As I was wiping it, I dried it with a towel, and rubbed it harder with the dry towel.
Something you can do is look up in the phone book for a shop in town that does car window tinting, or vinyl work, and ask them if you can buy a 12 in by 12 in piece of white or black (they'll have any colour you want) vinyl, and put in on the places your palms rest. It wont hurt your macbook and you can make it look like its not even there. If your in southern Ontario I'll do it for you. I'm going to post pics later of my macbook pro with a black dragon on it it looks really cool.