Hi. After changing the top case of my Macbook white for 5 times because of discoloration problems, I'm freaking out and get here to see if somebody could give me some advice. I bought my Macbook last November. Each time the yellow spot appears right after 2 weeks and becomes more and more serious and it's really disgusting... However, I don't smoke, I'm very clean, I don't put any cosmetic nor any cream on my hands since the first time I got my top case changed. I called Apple care and they refused to do anything about it. They say it MUST be due to the contact between the skin and the plastic, otherwise saying, they don't trust me that I didn't do anything that are not supposed to do to my mac. Now I see that some other people have similar problems since the discoloration appears despite the protection of skin contact. I'm convinced that there's problem under the top case of mac. But the technicians at Genius bar said they know the structure of mac and there's nothing under palm wrest and shouldn't be problem of heat. Are there still people like me who still have the discoloration problem NOW? (Apple said after the 2006 discoloration problem, the plastic has been changed.) I really want to know if it's the problem of my mac or it's the one of my skin?!