This 300ml bottle of brush restorer from Rustins removes dried paint, varnish and polyurethane from brushes and rollers. Pour into a glass or metal container so that the roller or bristles of the brush are covered.
As it may take some time for paint to soften, cover the container with cling film or foil to prevent loss of restorer by evaporation. As the brush softens, the restorer penetrates faster. When bristles are softened, rinse in water to remove all loose material.