Apple launched a new keyboard a short while back, you can see it here:
I decided to buy several for our office here after checking them out at a local retailer. They are very comfortable to type on, and the $49 price tag for the wired version is extremely reasonable (was the second cheapest keyboard at the store not factoring in the $9.99 entry level generic ones).
It dawned on me after buying it that the white keys would become brown and dirty over time- it is bound to happen no matter how clean your hands are when you type. Heck, it should have dawned on me when using the floor model at the store since many of the keys were brown and marked up.
Well, we've been using the keyboards for several weeks now and none of them have gotten dirty. Except yours truly dropped a pen on one, which managed to put ink lines on several of the keys. I went to wipe them off with regular electronic cleaner, it didn't even lighten the ink color. I then tried a basic all purpose cleaner, and still the ink marks were as dark as always. Before giving up I decided to try applying some Expo white board cleaner, recalling how I had once accidentally used a permanent marker on our white board and was able to remove it with the same cleaner. What do you know- it worked like a charm on the Mac keyboard. It took the ink off in seconds, the affected keys look just like new.
I am not cleaner savvy, so to some of you this may be obvious based on solvents or something. But for those of you like me, if you mark up your new Apple Mac keyboard, try putting some white board cleaner on a cloth and applying it to the keys. I have only done it one time and it did not affect the letters on the keys. However I should note again I am not cleaner savvy, so who knows, maybe the white board cleaner could have some adverse affect like rubbing off the letters if used to often. So be cautious. But it definitely removes ink stains!