I am looking for a simple way to significantly reduce the amount of dust in an appartment without fan or filter. Methods I have thought of:
Place a bowl of water on the radiator and put a drop of detergent in the water. This should increase humidity and catch dust
Place duct tape or a roll of tape (the stuff that is used to remove dust off clothes) on a radiator. As air circulates around the radiator the tape should catch a lot of dust
Place a sticky-fly-trap near a radiator (this kind: http://www.amazon.de/gp/product/B004ANTUBI (in German))
But after some days of testing all of these methods don't produce any visible result (no dust sticking on them).
What do you think of these methods, do you have better ideas?