why not buy some iKlear? Apple sells it and recommends it. it has proven safe and effective on all their products by not only them but millions of users.
i know it is pricey, but for the extra i have peace of mind.
better than trying something you don't know if it will have any ill effect.
i would hate for you to try a cheaper cleaner and find some ingredient in there strips the finish of the keys or reacts to the aluminum and turns is color.
because you have to use it to know, by that time it is too late and your baby is F***ed up!!!!