09-17-2013, 06:23 PM
Could it be staple fiber? On cheaper "builder's grade" carpets, there's a lot of loose staple fiber. But if it's occurring on more than just "builder's grade" carpet, or on wool where staple fibers are the norm; then I'd recommend switching to the soft brushes. In fact, I think you will always be happier using the soft brushes for residential carpet.