Buy the best real lambs wool mitts you can afford.
With
soft-bristle brush vs lambs wool, my theory is that grit could be caught up by a loop or tangle of loops in the wool, with nowhere to go, and dragged across the paint causing scratches. With the bristles (
as long as you are not pressing ) loops will not form. Grit can only go one way which is up between the bristles away from the paint.
Yes, one pass of a wool mitt or cloth will normally suffice whereas I find I have to go back and forth with the broom but I think that kind of proves my point.
With mitts or cloths it is mighty hard to resist the urge to press. With the broom, as long as you hold the handle away from the head (e.g. over a meter), and keep your hands e.g. not more than 40 cm apart to minimise leverage, then the pressure is mainly only from the weight of the head.
