Probably: lead used for the manufacture of pots or other objects. Cf. pot metal, n. 1a. rare.

Lead added to gold or silver in a smelting furnace in order to reduce the melting point. Also: lead ore containing silver.

Lead obtained by resmelting the slag obtained from the initial smelting of lead ore. Cf. grey slag n. at grey, adj. n.compounds 1c(a).

†(a) a large vessel used for fermentation (cf. lead, n.1 5a) (obsolete); (b) Metallurgy lead as it comes from the smelting furnace, containing…

attributive. Designating a pure form of white lead manufactured at Clichy in France, or the process used there to produce this, as Clichy process, Cl…