Upgrading RAM in your MacBook Pro 13" or 15"

Step 10: Cleaning dust (optional step).

If you like to clean, then it's time to pickup that microfiber cloth and collect some dust, which tends to deposit inside your computer especially around the fan exhaust area. If you have a pet, you'll see a lot of hair in there too, don't be surprised. You can safely clean the aluminum cover and small flat areas of the computer, like the battery or the hard drive, but leave the electronics alone and don't touch them with your cloth.

After taking the cover off, don't stack it on top of the exposed parts of the computer, find another clean spot for it on the table.