my recommendation. . . soap and water, on your hands, gets rid of all the nasty stuff that builds up on a keyboard or eats away at the painted on letters.
that, or get an external keyboard. if you really pound the keys hard (and thus the keys are worn from friction of use, not from dirty hands) then you can abuse your external keyboard while you are sitting at a desk, so there will be less abuse on the keyboard of the laptop when you are using it on your lap. Apple's BT keyboard is great. it is extremely compact (but the keys are in a full size layout) compact enough that you could travel with it.
I have to bath before using my computer!? Man that sucks.