There have been pictures of white MacBooks with “oil” residue from hands resting on the notebook, and I can see small spots where this could eventually evolve into something nasty on mine.
Enter the Marware Protection pack for the white or black MacBook. It includes a wrist rest and a microfiber laptop keyboard cover. It says that it leaves no residue when removing. Sounds like the perfect solution.
They also make one for iBooks, PowerBooks, and MacBook Pros. All models are only $19.95, well worth it if you ask me.
Update: It seems as if the yellow color is occuring even if there is some sort of shield or protection on the MacBook. This is not simply an issue of cleaning your hands everytime you use your system, it’s a issue in the design. Apple needs to come up with a solution ASAP. For now I will be using my Marware Protection Pack to cover up the yellow that is starting to show, but this isn’t a permanent solution.