Specially formulated for Holbein Duo Aqua Water-Soluble Oils, Holbein Brush Cleaner is non-flammable and odorless. It can also be used with other water-soluble oil colors.Holbein's mild cleaner offers extra protection to the bristles of your brushes; providing a better solution to maintaining their condition than soap and water. It also works well on both acrylic and watercolor paints. Allow the brush to dry completely after cleaning before using them again.