If you pre-wash your dog hair before spinning, be very, very careful not to felt it. I've never tried to pre-wash but have seen several attempts by others (experienced spinners who know how to wash fibers) that have become felted and therefore not usable. Apparently dog hair, the soft undercoat anyway, is very prone to felting. I helped a friend this summer run a bunch of dog hair through my picker. We only saved about half of what she had.