Aishu can extract copper from copper sulphide (Cu₂S) and copper(I) oxide (Cu₂O) using a process called auto-reduction or self-reduction.
When copper sulphide is heated with copper oxide, they react to produce copper metal and sulphur dioxide (SO₂).
2Cu₂S + 3O₂ Heat→ 2Cu₂ + 2SO₂
2Cu₂O + Cu₂S Heat→ 6Cu + SO₂