I have a small compressor that I bought at Costco for about $100 - it is
a high-speed oiless unit for small jobs like finish nailers and low-demand
air tools. I use it to fill auto tires and such... and to blow the gunk
out of electronic and mechanical Stuff. It came with a nice regulator
installed, and does not entrain oil or water.
Another thing to consider are the small diapragm compressors for
airbrushes. The one I used to have had a high-pressure shut-off so that
it ran only when the air was flowing... only made a few PSI and was da
bomb for electronic work.
Larger aquarium pumps also will do nicely.
Very high-pressure, high-velocity air streams can do a lot of damage -
use a good regulator on your compressor, turned down to 15 or 20 PSI, and
use a blow gun attachment with side relief holes and a rubber tip.
ALSO mind the static build-up, which can be considerable during
low-humidity operation.
Cheers
John