A salt melt of alkali and/or alkali earth chlorides and fluorides, heated to 50.degree.-100.degree. C. above the melting point is employed to purify heavily contaminated scrap aluminum. The scrap aluminum, preheated to 400.degree.-500.degree. C. is added to a melting or holding furnace containing the less dense salt melt, the mixture stirred if necessary and then held at the above mentioned melt temperature for at least one hour. First the sedimented metal phase, then the salt melt are filtered through a resistant open pore ceramic filter and thus freed of solid impurities. The aluminum is transferred to an electrolytic cell for purification, and the molten salt melt recycled.