I use the bundled cleaning cloth to clean the screen. As for the keyboard and aluminum part, I just use little bit damp tissue paper to clean the dirts.

I would suggest try mild soap water before using alcohol. Not recommend to use alcohol for cleaning on electronic products. Reduce the risk. Who knows if alcohol accidentally diffuse into the internal circuit board... LOL

Found this on the MB Owner's manual:

Cleaning your MacBook When cleaning the outside of your MacBook and its components, first shut down your MacBook, unplug the power adapter, and remove the battery. Then use a damp, soft, lint-free cloth to clean the computer’s exterior.
Avoid getting moisture in any openings. Do not spray liquid directly on the computer.
Do not use aerosol sprays, solvents, or abrasives that might damage the finish.

Cleaning the MacBook screen To clean the MacBook screen, first shut down your MacBook, unplug the power adapter, and remove the battery. Then use the included cleaning cloth to wipe the screen. Dampen the cloth with water if necessary. Do not spray liquid directly on the screen.

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Ok, if it is really necessary to use alcohol, be sure it is highly diluted.
Check this out:
http://www.computerhope.com/cleaning.htm