This just out from Apple :

Apple products are made with a variety of materials, and each material might have specific cleaning requirements. To get started, here are some tips that apply to all products:

• Use only a soft, lint-free cloth. Avoid abrasive cloths, towels, paper towels, or similar items.
• Avoid excessive wiping, which might cause damage.
• Unplug all external power sources, devices, and cables.
• Keep liquids away from the product, unless otherwise noted for specific products.
• Don't get moisture into any openings.
• Don't use aerosol sprays, bleaches, or abrasives.
• Don't spray cleaners directly onto the item.

Is it OK to use a disinfectant on my Apple product?
Using a 70 percent isopropyl alcohol wipe or Clorox Disinfecting Wipes, you may gently wipe the hard, nonporous surfaces of your Apple product, such as the display, keyboard, or other exterior surfaces. Don't use bleach. Avoid getting moisture in any opening, and don't submerge your Apple product in any cleaning agents. Don't use on fabric or leather surfaces.