your insides? or your computer's?

Sucking is always better than blowing.
With all power off, disconnected, drained, and earth grounded, "obviously".
;?)

Tim, perhaps both!

Whew... good thing I don't keep pets in the basement with the editing machine & the wood furnace! For a second there I thought I'd have to open it up! :)

"Sucking is always better than blowing."

I don't happen to agree. There is no way a vacuum cleaner is going to be able to completely suck the dust out of a CPU heat sink or the inside of a power supply, for example.

all depends how hard you suck ;P)

I agree with John, for the simple reason that an air stream can be directional, while sucking action needs tremendous power to achieve the same results. However, a small brush in combination with vacuum can clean out some narrow spaces, too.
Tor

After you get the big dust out then dunk it in triclo if you can stand the fumes. Of course there are drawbacks like all of the oil removed from the fan bearings and cancer. We used to spray our electronic equipment hot and running to prevent down time. All the dirt would flow out onto the floor.
JJK

I use the blow and suck method. I use canned air to blow with the nozzle of the vacuum cleaner back a bit from the part to stop the crud going back into the works.

That said my Antec DF 85 case has three air filter that do a pretty good job of keeping the dust out of the case. The DF 85 is an improvement on my previous Twelve Hundred as the filters can be taken out for cleaning without the need to slide out the drive bays.

Bob.

I do take my computers outside to blow them out, I use a 150 PSI compressor with a concentrated nozzle and it would make a real mess in my office if I did it inside.

I thought they were the same! :)

This one area where I come down on the blow side for movable devices.

Conventional wisdom suggests that forcing dust and dirt into small spaces and parts with forced air is more likely to be detrimental than vacuuming, even though the latter can cause transient static charges in dry environs. The folklore "don't vacuum your keyboard" has been debunked, but I still wouldn't do it when powered up.

Musicvid,

maybe so, but every engineer I have worked with has told me to always use compressed air to clean electronics and never use a vacuum. We keep a compressor where I work with a dryer attachment just for that purpose.

Dave T2

I thought they were the same! :)

They are! People are arguing over half full vs half empty! :)

Well, it's not a debate we'll ever finish here. My field tech training didn't allow compressed air inside the box. I have a client who is an aerospace engineer at Lockheed. I'll ask her what she thinks tonight.

SOT:

Going back into ancient history, I worked at a high tech company (in an era where an Osborne 2 was a portable) where someone decided that the contacts on boards should be burnished with pencil erasers before inserting them in the motherboard. A year or so later everything was a mess.

For sure we won't agree. The engineers I worked with include the ones that designed and built the DaVinci Color Correction system and currently build and maintain Resolve systems as well as have patents for various other hardware electronic systems. ;)

But either way, keep your computers clean.

Not meaning to come off as a jerk, but I have to trust these guys.

And yes this argument happens everytime we bring up cleaning your computer, so I take none of it personal.

Dave T2

I usually vacuum first to get out the majority of the loose crud. Then i use compressed air to get the little bit of remaining stuff stuck in the little crevices without blowing the first 95% out in a huge icky cloud.

"My field tech training didn't allow compressed air inside the box."

There was a lot of harmful bunk taught over the years based on myths.

One of the classics was how solder joints were supposed to look. No doubt millions of man hours were expended "touching up" joints that in fact degraded the quality of the joint. Apart from a joint that has completely failed it's impossible to tell the quality of the joint by visual inspection. The critical factor is the thickness of the copper / tin / lead alloy layer formed when the solder is liquid and the copper dissolved into it. That layer is mechanically weak and the thicker it is the more likely the joint is to fail. Repeated heating of the joint to "touch it up" increases the thickness of the layer and hence weakens the joint.

Fortunately all the myths about compressed air and vacuuming are harmless.
It's no easy matter to create a differential electrostatic charge on a finished PCB assemby. The thing is full of conductors which will work to allow the charge to equalise.

Things that compressed air is risky around:
Fans, you can spin them up to an extreme number of RPMs with compressed air. Probably not a healthy thing to do. If one flew apart it could be nasty.

Lenses. Serious risk of forcing crud inside the lens assembly that'll cost a lot of money to get out. ONLY USE PUFFERS to blow dust off lenses.

Insides of DSLRs. The shutter is comprised of several very thin interleaved blades of teflon. We've had one shear a blade, possibly because the blades became tangled and the next time the shutter operated it was sheared off by the other blades. Neither us nor Canon are entirely certain how this happened, Canon had not seen this before. Maybe compressed air had nothing to do with it. We have had other weird damage done to the innards of 5Ds almost certainly done by idiots trying to jam an old film lens into the camera that has rear elements that are too large or long for a DSLR.

One other word of caution regarding cleaning.
Modern PCBs are cleaned with water. I'd be a tad nervous using any other solvents to clean them. Probably most are safe but it's possible that today some components contain material that will be affected by the old school solvents, proceed with caution. Ethanol or Propanol should be OK. Turco, freon etc don't know for sure.

Bob.

"Lenses. Serious risk of forcing crud inside the lens assembly that'll cost a lot of money to get out. ONLY USE PUFFERS to blow dust off lenses."

Yes, the factory certification I mentioned (Kodak, Noritsu, Technicolor, Pako, and others) was on optoelectronic and zoom lens assemblies and controllers ($50-150K range) for commercial photo printers. I once got yelled at for using DustOff inside a box. So the training I received seems consistent with your advice.

Also, using compressed air on cpu coolers, besides spreading dust all over, can force dirt deeper between closely spaced fins, not something I find particularly palatable.

"Also, using compressed air on cpu coolers, besides spreading dust all over, can force dirt deeper between closely spaced fins, not something I find particularly palatable."

I think it's a bit of a swings and roundabouts problem. Much of the "stuff" that gets inside a PC is flakes of dead human skin. You get that on something that gets hot and it could be fried onto the surface and only mechnical abrasion or a solvent will get it off. If possible I remove the fan so I can get a clean shot in between the fins to blast as much out as possible.

My own solution to all these issue is to tackle the problem at the source by keeping positive air pressure inside the case from filtered air. Decades ago now I used to work for Leeds & Northup. Their old school electromechanical devices such as chart recorders had an air feed port on the back. In really hostile environments, low pressure, regulated, filtered air was connected. I though that a bit extreme until I worked inside some racks next to a lime kiln.

We'd also had an issue around mines and steel works with grit ladden air abrading away the pins on ICs.

Bob.