I use a can of spray for the laptop periodically. As long as your machine is switched off, I generally let mine cool down too so the cold isnt too much of a shock for it, and you dont blast it for too long it should be fine. Spray into the bit where the fan sucks air in and it should force any dust and creepy gremlins out. If you have more than one fan on your laptop – then rinse and repeat! I also find a wee spray from a few inches away in the reverse direction helps to loosen build-up then back in the air intake bittie. As for your ports and CD tray, I don’t do mine but then I don’t see much gunk in there either. Oh, and I also use mine for the keyvoard – a wee skoosh – again from a few inches away will get rid of those dust bunnies hiding in your Laptop. It’s normal for any C02 can to get cold as you use it. Try not to spray it for much more than about 5 seconds at a time.