I take my pc to work roughly every 6 months and put the compressor to it, does a wonderful job, every month i may open is and show it the vacuum cleaner but only for superficial stuff
One thing - always be careful with compressed air and electronics, the two sometimes don't mix...
I used to work on ships as an engineer, and we always had several PCs in the control room for looking up manuals and service guides. But then we ended up printing out the relevant pages and taking them down to the workshop. Massive waste of paper, annoying if you forgot a page, and a lot of the diagrams just didn't have the required resolution on A4 paper.
The PCs were normal Dells and replaced every 18 months as a matter of course as they rarely made it to 2 years with the levels of vibration.
So we took one of them down to the workshop to use for manuals.... we fitted a couple of bits of filter wool over the fans to keep most of the crud out. But one day the machine kept on restarting... so we opened it up, and it was covered in a fine mist of probably lube, diesel and hydraulic oil. Normal method to clean this kind of mess up would be the blow gun, which someone decided to use, despite the rest of us advising caution. It may or may not have been the chief engineer.
Needless to say, the PC didn't make it out alive. The first thing that signalled an issue was the "wheeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee" noise as the CPU fan was brought up to about 100,000rpm before the bearing failed. Next, some of the electrolytics were peeled off the board. Best yet, and we only found this afterwards, is that some of the oil mist ended up in the hard drive casing - I think the solvents and air pressure were enough to get into the casing past one of the sticker.
But better still was on another ship. The RPM and torque output (and hence power) of the main engine is measured with a pair of optical tachometers on the prop shaft - it detects how much the 1.2m diameter prop shaft distorts. We were woken in the middle of the night by an alarm which was a fairly worrying "main engine slowdown" (these are normally caused by an oil mist detector, warning of the possibility of a crankcase explosion).
Power meter:
Prop shaft:
On heading down, we found the issue was that one of the two tachometers had failed, and this had caused the indicated power output to jump to several hundred MW, way above the normal maximum.
They are similar to the break beam detectors on many tachometers - a disk with many cuts in it, and a pair of IR break beams, set up so the direction of rotation can be detected. We figured it was just crud blocking the beam, but couldn't work out a safe way of removing and cleaning the sensor with the engine running.
So some bright spark, who may or may not have been the first engineer, decided to use compressed air. Now, I don't know exactly what happened here, but I think that the very thin slit disk was deformed by the air, causing it to impact with the sensor. Needless to say, the 80MW output of the engine was more than a match for the sensor and disc, which ended up wrapped around the prop shaft, ripping about 15m of assorted cabling from a loom before something finally snapped. Quite a few cables were severed or shorted.
The first thing to go out was the engine room lighting were we were, which I think was our first indication that things were about to get interesting. Then practically every single alarm was indicated (bar the CO2 flooding system, which is on an entirely different circuit it would seem).
It was about then that we felt the first shudder of the main engine going into an emergency shutdown (i.e. stopping as quickly as it can). It turns out that this was because the same loom had several of the main crank bearing temperature sensors on it.
Anyway, long story short... we also managed to short half of the PLC power supply system, which meant that not only did the main engine shut down, but none of the generators started up. We suffered a total blackout and spent the next 45 minutes trying to get one of the five generators back on line. It was a good few hours before we had the main engine back up, and had to work watches because we'd lost so many engine room alarms.
Different life as a software engineer now, it has to be said. Sorry for going a bit off-topic, but just needs to be said, always think before using compressed air to clean something!
Some pics of the ships:
http://www.flickr.com/photos/cybergibbons/sets/72157594324779107/http://www.flickr.com/photos/cybergibbons/sets/72157600000178587/
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