My suggestion of compressed air came from my telecine days. If you were running a film 'live' on air and got some fluff in the optical gate you couldn't just stop the film, open up the gate and wipe the fluff off as probably quite a few million people would notice you doing so! So, the practice of blowing compressed air across the gate whilst the film was still running was always top of the list to try.
Someone once did try and blow the fluff out with his cheeks puffed out, when he blew - out came rather a large quantity of the fruit cake he was eating at the same time. Think they had to stop the film whilst he was on air for that one!!
