Make your own dust filters for your PC case
 

The obvious filter material for a PC intake is that used for screening dust in a vacuum cleaner filter pad, since this material is designed expressly to perform this function. To get started, you'll need to find something to hold the filter material in place over the intake on your PC's case. You could stick it in place, but that would make it hard to replace periodically. Fortunately there's a ready-made holder for the filter material in the form of a simple J-shaped plastic extrusion.


Since installing filters and nano-ceramic fans, not a single fan has had to be replaced and all are continuing to run quietly and provide specified levels of airflow. Changing the filters on each PC takes around 10 minutes to cut the material to size and another 10 minutes to fit. That's just 20 minutes every six months, probably less time than it typically takes to download and install a Service Pack.

http://www.techradar.com/news/comput...your-pc-663270

I can see the new mods now... turn your computer into a room HEPA filter machine. ;)