mister clean magic eraser
go ahead and get the mr clean eraser. its completely harmless. the sponge is made out of some crazy soap, and does wonders for my iBook. DONT wet the sponge though, cause when it gets wet it starts to dissolve, thus being a fantastic cleaning agent though if used wet it will use a residue on your laptop, though that can be taken off with a damp cloth. just take the sponge out of the box, and still dry, rub it on the track pad and palm rests and...well....the rest of the ocmputer. its completely harmless on the shiny plastic of the clamshell and on the keys. also, unlike nail polish remover (which idiot me tried once.) this will not take off any of the writing on the maching, I.E. the Macbook name, serial number, anything.
if theres a really tough spot of dirt or palm oil that wont come off, then wet the sponge a LITTLE, just enough so that if you touched it youd be like, oh, thats a little damp, not like, woah, dont touch that, its soaked.
mr clean erasers are like 4 bucks for a 4 pack at Target. theyre amazing.