After a brush has been cleaned the cleaning agent needs to be itself removed from the brush. This is especially true in the case of oils, or where spirits have been used. Our brush soaps are designed specifically for this. In addition they have in them animal fats, which put the natural lubricants back into your natural hair brushes. Recommended. Wash the brush soap itself out with warm water, shake out the brush and leave standing upright in a jar with the bristles exposed to the air.