Sunddenly one of my laptop's fan became noisy. It is summer and hot inside the houses here in France, hence I immediatly decided to change both of them by security without trying to find wich one started to have a break down. Ordered on Thursday, received next Monday => great experience !!
I performed changes in less than 10 minutes, because I have the right tools and already undusted fans in past !
Of course, before touching the mainboard, I have disconnected the battery to avoid any electric shock.
A soft brush can be very usefull for the first clean-up inside. Of course, perform that very very carefully without pressure : this has to be like a caress ! Then an air-spray is also very usefull, and do not forget to put screws far from the laptop when spraying (lol) ...
I guess that this is a safety method compared to the use of a vacuum, that can dramatically damage components, even more in such laptop !
MacBook Pro 15" Late 2008 through Mid 2012 excluding Mid 2009 2.53 GHz Left Fan
MacBook Pro 15" Late 2008 through Mid 2012 excluding Mid 2009 2.53 GHz Right Fan