My powerbook palm rest is getting very dirty. It has blotches that simply can't be washed out. I've only tried using a damp wet cloth. Has my sweaty/ greasy palms eaten through the aluminum? Is there any hope to clean it or wax it or buff it out?? btw I've only had this powerbook for less than 1 month!!!! But I use it everywhere I go and the wrist area is starting to look nasty!!!