As part of my regular maintenance on my brushes, when they're dry, I comb them through with the coarse end of a comb. I'm convinced it helps in their cleanliness and keep the knot in great shape. I would guess most think it's either unnecessary or a little whack but after years of doing it, all my brushes (mostly badger but one boar and one boar/badger mix) have held up quite well and look good. I just lightly comb up from the bottom of the knot to the tips and across. Lightly is key. I comb my hair after washing and drying so it makes sense to me (even if no one else!).