do you mean clean the vents by blowing air into them or open up the laptop and do it?
Whatever fits you best. I actually use a vacuum cleaner on my Little Brothers laptop, I know it isn't recommended, but I have never had any problems - 5 years still going strong. Just make sure the laptop is powered off and you don't use too much power.
Also you have to take it into perspective. A laptop WILL become so much hotter than a desktop. My own laptop hits 89 celsius in League of Legends and it's 2 years old. So only if it actually affects performance or shuts your PC Down you should worry. The PC should also be quite new right? So if it happens, then you still got the warranty.