I haven't looked in my computer box for about 6 months I was surprised that was so much dust. It was everywhere, the small fan on the cpu was completely blocked the power box fan was blocked. These parts were almost hot to the touch.
My new place is all hard wood floor and the dust bunnies are more noticable than my last house (carpeted)I assume that this might be the culprit for the amount of dust in side the box.
In any case I just wanted to share this cause there might be others out there with a dirty box.
Also, when I bought compressed gas for electronic equipment I found those cans to be really expensive stuff. What I did find was Costco sells these cans in packs of 4. So if anyone needs a can PM me I've lots more.