You could use compressed (clean) air to blow the dust out.
But the best way it still to open it up and clean it by hand.
As for the fan best place, there is no place where it's good for everybody
At the bottom it will heat your lap if the machine is there.
The right, it will heat up other people.
Top? Can't be done as the battery and hinges are there.
Sorry mate, there is no good place to put it, else they would have put it there