Just an FYI - I recently had a scare with my G4 iBook. After returning from vacation, I removed it from it's case to find that the lining of the case had stained to iBook case. The manufacturers of the case are looking into it, it seems that the plastic of the G4 iBooks is more absorbent than that of the G3s. Given that, I imagine that it is possible for someone else to have a similar problem. A trip to the Apple Store revealed that it is entirely safe to use the cleaner "Simple Green" in it's concentrated form. It did leave the iBook a tiny bit sticky though, so I cleaned off the residue with iKlean. I did,m of course, make sure not to get any on the screen, I don't know that it would be as harmless there.