Cleaning the inside for dust

With top deck (part with keyboard) removed, with the laptop open and on it's side use a paint brush and canned air. This will allow the dust to fall out of the laptop and not just get smeared around. You can clean the fins to the heat sink after the "general cleaning".

To clean the fins on the heat sink:

With the laptop sitting on it's bottom and opened. There are 3 screws and a piece of tape that hold the fan in place. Unhook the wire to the fan. Remove the 3 screws, do not remove the tape. Gently lift the fan up using the piece of tape as a hinge. Blow out the fins with canned air. Reseat and secure the fan. Then hook the wire back up.