If you want to do it on the cheap (and don't have a stack of computer fans handy), you could do a lot worse than a bathroom extractor fan with a suitable filter media attached across the inlet.
Kitchen extractor filter papers, felt, glass fibre matting as used by Thor, car air intake filter, vacuum cleaner bag - all would serve to remove dust pretty effectively and could just be vacuumed off to clean them.
Obviously no EU or HSE standards would apply!
Duncan