Chromium salts were until recently extensively used in dyeing wool with synthetic mordant dyes. Copper sulfate can be used as a mordant in vegetable dyeing. These dyes are called "adjective dyes" or "mordant dyes". The madder dyestuff is combined with a dye mordant. It also finds use in wool dyeing as a mordant. Solutions are used in dyeing as a mordant, and as a coagulant for industrial wastes. Morrissey's complex, literate lyrics combined themes of ordinary lives with mordant humour. About 25% of produced oxalic acid will be used as a mordant in dyeing processes. It can be used as a mordant in dyeing. Ferrous acetate is used as a mordant by the dye industry. They may also be used as a mordant in dyeing. The technique of mordant dyeing was prevalent in India since the second millennium BC. It features some of Zevon's trademark mordant irony. The dye color is fixed in the fabric with a mordant. A yellow dye can be produced from this plant with alum used as a mordant.