In agreement with wickedG35, the Magic Eraser worked some serious magic on a totally dirty aluminum mac keyboard which I adopted. You can see the before and after on my blog. It's like night and day:
http://www.leftylimbo.com/2011/06/how-to-clean-a-mac-keyboard-with-a-magic-eraser/
As mentioned in my article, I squeezed out virtually all the water from the Magic Eraser and even blotted it with a paper towel before applying it to the keyboard, using very, very light pressure. You do not want
any water dripping into the keyboard!
Afterwards, I did the same to my MBP 15" unibody, which wasn't half as dirty but still needed some spot cleaning here and there. Totally awesomelooked practically brand new. Note though, that I did
not use the eraser for the monitor screen! I'm planning on using iClean for that.
Now that there is mention, though, of permanent damage and/or discoloration of the aluminum due to our body's oils, I'm definitely going to get a protective "skin" for my MBP15. I found the transparent guard from Skinstyler to be especially appealing, since I can submit my own custom artwork to be printed on it. Check it out:
http://www.skinstyler.com/custom-wrist-rest-trackpad-protection-skin-transparent-p-497.html
I think this, coupled with the silicone keyboard protector from Marware, just may be a great solution. Any thoughts?