My new Rosewill case has a dust filter for the front intake fan. I read some good comments about it but since it just arrived I can't tell you how effective it is.
However, when using a vacuum cleaner it's wise to make sure everything is grounded to each other and to earth ground. Try not to get the motor too close to the components in your case. I know from my days as an electronic tech. that vacuum motors can reek havoc on VCRs, so I imagine they can't be too good for computer parts.

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