Jeffrey,
You can use isopropyl alcohol to clean both the screen and the keys. This can be purchased as Isocol (rubbing alxohol) at Coles, Safeway (Woolworths) or many of the smaller independent supernarkets.
For cleaning the screen, take a tissue (Kleenex) and fold it in half, then roll it into a cylinder. Moisten the tip with isocol, then use the tip to swab the screen. If you apply too much pressure, then you will bend the tissue. Trim the end off as it becomes soiled, and repeat. IT will take time, but you can get it clean eventually.
To clean the keyboard, you can just use a folded tissue with isocol. Hold the iBook upside down and, whille it's off, rub across the keys to remove the accumulated grime. You don't need to do it too hard, just do it gently and frequently until all had been removed.Then leave it inverted until all is dry (say half an hour). All up, it should take no longer than an hour to get your iBook back to a pristine appearance.
Doug
(Werribee, near Melbourne, Vic)