NOTE: Some contractors prefer to leave Red Professional on light shadows overnight to fade out shadows when used on sandstone and other erodible surfaces. SoSafe Professional is ideal for use on concrete, blocks, stucco, stone and other porous surfaces. SoSafe has recently completed testing SoSafe Professional on synthetic flooring in trains and buses to remove marker pen stains with perfect results. Contact SoSafe for more information on the compatibility of SoSafe graffiti removal products for your specific application.