corrosion on the bottom of my macbook

Since i have purchased my Macbook Pro i haven't done as much travel as initially expected so it has almost exclusively sat on top of the box it came in next to my tv.. i use it everyday with a wireless mouse and keyboard and only put it to sleep so they can wake it back up. it is connected to a 32" flat panel. today however my routine just changed a little so i needed to take my Mac with me and it has white build up all the way around the underside where it has been sitting on the box. it doesn't come off which is why i think it is corrosion has anyone else has this type of problem? is this a issue apple would cover under warranty. obviously this mac due to never being touched is in pristine condition other than this now. kinda a bummer..

That's a new one. Aluminum can degrade via severe and continuous abrasion (think airplane parts or automotive fasteners) followed by contact with certain oxidizing agents. Has it been in contact with any cleaners that contain chlorine or bleach?

If you live in a humid climate the cardboard box may have absorbed moisture from the surrounding air. That moisture may have caused deterioration of the cardboard material and in the process transferred the coloring to the bottom of your MBP. I would try to remove it with alcohol or maybe another mild cleaning fluid. Just be super careful not to use too much! Use a cloth and apply the alcohol or cleaning fluid to the cloth not directly on the case. With luck you can clean it off. And by the way, that's not something Apple will take care of under Apple care.

thanks for your responses.. i am going to get some alcohol swabs from work on monday..