transitive. To make pure or clear; to remove extraneous matter from; to clarify (a liquid, esp. wine or beer); to refine (metal). Also with down.

In obsolete Physical Science: To bring (metals, minerals, etc.) to their perfect or mature state by heat; to ‘maturate’. Obsolete.

transitive. Metallurgy. To purify or separate (metals) from dross, alloy, or other extraneous matter by removing oxides, carbon, and dissolved gases…

transitive. Metallurgy and Alchemy. To purify (a metal); to convert (an ore, etc.) into pure metal. Obsolete.