Dross

[Oralee]

the scum formed by oxidation at the surface of molten metals

[Laresvog 0]

worthless or dangerous material that should be removed

[Tayyaba]

Waste or impure matter

[Thomassew]

Residue that forms on the surface of a metal from oxidation

[Britney]

The impurities in metal

[Donald Trump]

A waste product from working with metal

[Tjalfdyed 0]

Dross is typically waste or impurity that is removed from a finer material during a smelting or refining process. It can also refer to something considered worthless, substandard, or inferior.

[Laresvog 0]

the scum or refuse matter which is thrown off, or falls from, metals in smelting the ore, or in the process of melting; recrement

[Williebit]

waste matter; any worthless matter separated from the better part; leavings; dregs; refuse

[Lanell]

dros, n. the scum which metals throw off when melting: waste matter: refuse: rust.—n. Dross′iness.—adj. Dross′y, like dross: impure: worthless. [A.S. drós, from dreósan, to fall; cf. Dut. droesem; Ger. druse.]