Too much information.
A vacuum or can air both can cause a static build-up. A vacuum is a bit more dangerous because most at home use is from the house-hold vacuum that have metal ends that can cause a bigger zap. If you are going to use them anyway, a few precautions:
- use the vacuum on the outside, put the brush end on it to shield the metal end.
- use can air in the various external tight spots, use short bursts. Do not position the can in a way to cause liquid to be sprayed out. Take care around the fan(s), it can cause the fan to spin-up to high rpm's resulting in the bearing lubricant to be spun out. DO NOT spray any of the electronics.
- do not clean it on a dry day, try and find a humid day to do your cleaning. The humidity in the air will keep the static down.
The thing about static around electronics is insidious; a static discharge as low as 50 volts can result in a hole being punched between the layers within semiconductors. This kind of damage may not result in a immediately failure. Over time, material from one layer will start migrating to the other through this hole and eventually causing a short and of course failure of the part. It may take weeks or months before you find out that it was damaged. Most IC chips have clamps on the input leads to prevent some of the damage caused by static but they can only handle so much before it gets into the chips.