Nice find, but please don't blow compressed air into a fan without blocking its rotation. It will induce currents and can cause damage to your mainboard.
Even more important: do not blow air in the opposite direction of the one the fan is made to rotate. If you are unlucky you'll damage it, if you are very unlucky it will stop working enterely. Source: I broke a lot of them
Most motherboards (but not all) have basic protection for this, so it's quite unlikely that you break your motherboard electronically that way.
That said, blowing compressed air at a fan will spin the fan much faster than what it was designed for. So you still risk breaking the fan mechanically. Always hold the fan when blowing compressed air at it.
