scratch your paint with those things, ESPECIALLY BLK BIMMER PAINT! BMW Clearcoats are not especially thick and Blk shows imperfections much more than white. Heck, with white paint you have to practically scratch the paint down to the bare metal to notice it. I've got an M3 and almost everything I do to it can cause scratches, so rubbing a dirty duster across it does not help.
Where do you think all that dirt and dust goes? It's on and in the duster, then you rub it across the surface, causing micro-marring.
That thing is designed to hold the dirt on it's surface. Hard to "shake it out" and since it's not designed to be washed that dirt just stays there. Parrafin wax is cheap, chemically incompatible wax, it's not a high-quality carnuba wax designed for vehicle paint protection and gloss. Take my word for it, over time you will notice scratches induced by that duster and you will
kick yourself for using that thing, but it will be too late, once you induce scratches all you can do is mask them, they will always be there. (Unless you seriously buff your paint down, but that damages the paint also) You have immaculate new paint, keep it that way and trash the "Cali car scratcher".