These are genuine boar bristle brushes with densely packed fibers that effectively distribute oils across the surface of the walnut to ensure even patina of the walnut shell. The black boar brush is more suitable for starting the patina process. It contains natural oils that supplement the oils that are already on the walnut that from play to ensure that there is suitable amount of oils to evenly cover the walnut shell. The yellow boar brush is more suitable for daily cleaning and maintenance of patina and should be used in a later stage compared to the black brush. As these are genuine, natural boar bristle brushes, it is normal to have occasional breakage of the bristles. This is expected, and the brush should be treated as a consumable product, though it should last for a long time as long as you are not brushing very aggressively.
