Zest-It Cold-Wax Oil Painting Medium .A smooth, thick, firm paste that doesn't require heat. Mix with oil paint to give texture, makes impasto easier to achieve. Speeds up drying time, can be used with brushes, painting knife, shapers, rollers and more. It does not contain any Aromatics or CFCs, it's classed as biodegradable and therefore kinder to the environment - non-flammable. Thick - dries to stable finish.