Re: Positive Air Pressure
" A quick vacuum from the outside does the job, you could even tell the cleaner to do it, it's pretty fool proof."
Except the cleaner is 100% guaranteed to either
a) crash computer by pulling plug to power industrial vacuum machine
or (slightly smarter facility hygene operative)
b) plug industrial vacuum machine* into empty socket next to computer, thus tripping circuit
*floor polishers are also good for this, as we discovered by correlating our regular teaching PC lab failures with the caretakers weekly rounds...