I've tried that stuff and was surprised how little was in a can bad value !
A buddy of mine bought me a gun that takes catridges found in paint ball guns but they too run out super quick.
basiclly i think air blowing is dumb. in order for them to be effective they have to blow hard enough
and if they do you risk damaging your machine. There is resistors you need a magnifying glass to see everywhere
and if one is loose you will blow it clean off with a compressed air system. Not a good idea !
I would use quetips (cotton tip sticks) with either alchohol 99% (isopopenyl) or a half cup off warm water with a drop of dish soap mixed in.
and make sure to roll the tips on your pc parts not rub up and down or you can snag small parts and pull them off !
SO roll banck n forth and make sure its dry before you power up
ANd that package of que tips will last a million ties longer than canned air.
I'd also never clean a pc with out taking the opportunity to inspect the capacitors for bulging on th top
or leaking from the bottom etc It happens and when it does its bad ! ..about 3 weeks ago i had one explode on me
and it was like someone shot a gun off beside me lol ..scared me half to death lol