Is this the dirtiest PC ever?
 

"We acquired a CNC machine which was used for cutting MDF. I pulled the rack-mounted PC out thinking it may need some maintenance. It still fired up with Windows 95 and a warning that the anti-virus programme was 91 months out of date"

http://www.theinquirer.net/default.aspx?article=36876

i've seen worse...

yup, I've seen worse too. This is just some dust from grinding (slijpen ?) bricks, doesn't take that long.
A dirty pc is more something like this: