Try typing computer vacuum cleaners into Google. There are plenty and
plenty of reviews. The number things that can be most effective are
preventative. SHCS is the number one cause of congestive computer
buildup. Second hand cigarette smoke will cause that dust to stick.
Keep the air in the room as dust free by adding cheap solutions.
http://www.americanallergysupply.com/box-fan-air-cleaner.htm
I use several of these that I made myself. Fan,filter,tape. I have
four running at all times in my computer room and can say they work
better then any commercial filter on the market.
Vacuum cleaners are made for computer and other cleaning of even powered
up electronic equipment. The chief differences are carbon or another
semi conductive material added to the plastic, and spark suppression
capacitors on the brushes, as well as anti static bags.
Long ago, I got into a big hassle over this type of specialty vacuum
cleaners.
It had to do with (of all things) the paper bags. Seems that the GSA
rotated suppliers and wanted to substitute vacuum cleaners that were the
household type. When we finally got it through their heads that the
vacuum cleaners were special purpose, naturally the contract would be
expired, the order cancelled, and we'd have to start the process all
over again. We had something like ten thousand bags in inventory for the
original vacuum cleaners. (Antistatic bags, to boot!)
Finally, we had a stack of paper about a foot high documenting our
efforts, and a GSA exec wandered by on a tour, asking about problems.
Shortly after we showed the tour group the stack of paper, a dozen of
the correct vacuum cleaners showed up, current contract or not. We
didn't even get a bill!.
So yes, small shoulder carry vacuum cleaners suitable for computer use
are made. The price those days was almost twice that of a similar model
without the anti static and noise suppression options. About $100
instead of $59.95