Brush polish Is another name for spirit varnish. In a general way, 4 oz. of best shellac to lpt. of methylated spirit will answer for applying by means of polish rubbers. If the polish is to be applied with a camel-hair brush, it must be thicker say 6oz. to lpt. Some polishers mix equal parts of polish and best brown hard spirit varnish; it too thick, more polish or spirit is added; if too thin, add more varnish.