In Poling process of purification of Cu, O₂ oxidises following group of elements :

In Poling process of purification of copper and oxygen oxidises the following group of elements S, Sb, As and Sb, As, Fe.

Poling is a metallurgical process used to purify metals such as copper and tin (oxidized impurities). Metals with oxidized impurities can be cleaned using the poling technique. It is often used to clean up metals like copper or tin that are impurely formed as copper oxide or tin oxide, respectively.