Is the dust for them to use the potty in or for dust baths? I keep a dust bath in with mine all the time. They use it to use the bathroom sometimes, but I clean it out. The dust does have a tendency to settle on stuff. It came to my mind that the dust may not be good for their resp. systems, but lots of degu owners do this and noone has ever said anything about it irritating their degus lungs. For flooring, I have some cheap straw mats for them to sit on so they don't sit on the wire. Also they are okay for them to chew on. Also, in the top level that is a half floor, I put an Italian ceramic floor tile that they sit on. It stays cool, so if they get hot they can sit up there, and they can't chew it up. I just wash it off with soapy water about once a week. I do use aspen in the bottom. I just have to change it regularly. I know this is a pain, but I don't really know how to get around it. Oh, you can't be too thorough. It's good that you keep it so sanitary.