Ferric subsulfate (also called Monsel's, basic). Our Monsel's is always fresh with no precipitate. Monsel's will stain clothing if spilled on it. It can be removed in most instances with Delasco Iron Stain Remover . When cold, Monsel's suspension may separate but will dissolve after gentle warming and shaking. Available in 1 oz (30 ml), 2 oz (60 ml) or 1 pint (16 oz or 480 ml) bottles.