What about an air amplifier.

http://www.vaccon.com/air.html

I first came across them nearly 20 years ago when I was a uni and someone was doing a project on materials handling. The idea is a venturi is fed with compressed air, out of one end you get a high volume, low pressure blast of air, the other is a negative pressure air flow. Not a huge vacuum but it can pick things up, move shells etc.

My thinking would be a tube in a tube with the inner carrying an air feed into the chamber and the outer attached to an air amplifier and sucking the cleaner and debris out.

As an aside the guy doing the project had an idea that by attaching an amplifier on an carb he could get some boost, time ran out and he never did it, would have needed a large sized compressor even for the small engine cars we ran. (sounds like something to package and sell on ebay - nitrous amplifier LOL, would disperse well though)...