Does this happen to you while grooming (and another question too)?

Are you sure your using the stiff brush the right way? The curry should pull it all up, but the stiff brush should get it off the surface if your using it right. Make short quick strokes kinda flicking the brush outward as you go, if your doing it right the dust should be flicking right off. It's so hard to explain lol wish I could just show you, it would be so much easier... Anyways, I hope this helps!