Believe it or not, but toothpaste combined with water and soap makes it shine just like new. I used a piece of cotton cloth (actually it used to be a shirt) and soaked it in the soap water and applied some toothpaste directly on my iBook. Then started to rub gently and I couldn't believe my eyes... all the dirt/dust/stuff that makes the case appear kinda grey was gone. Totally worth a try! Works for the palm rest too.