If you know how to open your laptop, I would clean it out that way. Sometimes using compressed air on a laptop just pushes the dust further in.
Also, look up RightMark CPU clock utility. Their website can be found
HERE.
Before you download it and use it, go through the website, check out the forums, and learn the ins and outs. But trust me, best thing I ever did for my laptop.
In a nutshell, if you don't want to read the website, it allows you to control your voltages on your CPU(s). Laptops are almost always using much more voltages then is needed, thus you get a lot of heat from your components. And yes, I did a LOT of research on how it could effect your laptop in any way, good or bad, by changing the voltage, and its beneficial to use this program. I have had ZERO issues, and have lowered all my temps by 15 to 25 degrees CELSIUS. But please take the time to read over the website, learn the program, BEFORE using it.
Hope this helps.