The term 'Smelter's Stuff' refers to the materials used by a smelter in their job. The two crossword solutions for this term are 'ores' and 'ORE'. Ores are rocks or minerals from which valuable metals can be extracted, while ORE is a single rock or mineral that contains a valuable metal. Smelters use these materials to extract valuable metals from them, such as gold, silver, copper, and other metals.