I clean up my rig like every 3 weeks with a can of compressed air. I use it all up. Now I built it last year, for the first 3 months or so I cleaned it efficiently. Then, like 8 months later there's a layer of dust which is unremovable. I've touched some pcb's myself and I see that I can wipe the dirt off into dust bunnies with my fingers but I can't just finger-rub everything, and no matter how hard or how close I spray with the can it just won't remove. Since then I've even tried cleaning up every week but the layer of dust is still too stubborn to remove. I suspect that since in my country we've got high humidity (it's a small island surrounded by sea) the same humidity causes the dust to cake over and hence be unremovable with normal spraying. Any ideas as to what I can do? I manage to clean up the zalman cpu cooler with a small paint brush, it's very efficient much more than spraying with air, but obviously I wouldn't be daring brushing pcb's with a nylon paintbrush due to possible static damage!