The Retarder and Antiquing Medium is an additive used to extend the drying time of Jo Sonja paints and other acrylic paints. Blending of gradations can be done wet-over-dry as well as wet-on-wet. This medium is also recommended for use in brushes for storage. Clean up with mild soap and cool water. Also available in a larger size, JS303 Retarder & Antiquing Medium 8oz.