I have no idea but I did find this:
Cleaning your Xbox DVD drive
If you are getting constant dirty disk errors, what do you have to loose, give this a try. The majority of the drives are not really dirty cleaning it will not fix the problem, they are getting out of adjustment or just getting weak. Try not to get your hopes up, too much sometimes you will be improving a DVD from constant errors to less frequent glitching and pausing during movies and games. But I guess that is better than nothing.
See disassembly procedure here for details on how to get at your Xbox DVD drive.
Read all about it:
http://www.llamma.com/xbox/Repairs/cleaning_your_dvd_drive.htm