Metropolitan slipware jug, decorated with Xs, Ss, chevrons and foliate designs. Metropolitan slipware vessels were made in Harlow, Essex and were so-called because London quickly became their prime market. They are decorated with a trailed white slip underneath a clear glaze. Slip is a type of fine, liquid clay which could be piped through a nozzle to ‘draw’ patterns onto pots. Cow horns or other similar devices were used to pipe the slip.