There are actually three places to address. First, is under the keyboard. The keyboard can be "lifted/released" by depressing the "stays" that are located above the "ESC", "F5/F6", "Prt Sc" and "*" keys. Gently lift off the keyboard after it has been released and blow out the entire area with "canned air". Then, it's an attack on the cooling system. Use a toothpick to "hold down the fan blades" and blow air into each of the cooling system intakes on the bottom of the machine. I also cover the vents a bit so that there will not be any "back blasts" from this procedure. After you have completed this, remove the multiple screws that are holding the plate to which the smallest fan is attached (Memory/CPU Compartment). After you have removed the plate, spray that are with compressed air. I do this procedure twice since one step may force "crap" into the channels previously cleaned.
CAUTION: I would recommend that the unit be unplugged from the A/C power source and that the battery be removed prior to starting. This is because compressed air, if "angled incorrectly" or applied too close to a surface area will cause condensation and may cause some electronic components to "short out".
Finally - Turn on your laptop and immediately depress the Fn+F10 sequence to activate the "Max Fans" state. Run the unit this way for about three or four minutes to insure that anything loosened by the cleaning procedure is ejected from the system.
Good luck and let us know if this works for you.