During smelting it's the waste material floating on top of the molten metal

Below you can find the During smelting it's the waste material floating on top of the molten metal Jeopardy Words Answer. The answer to During smelting it's the waste material floating on top of the molten metal has 4 letters. This clue belongs to the Science category and is part of Jeopardy Word Level 157. If you scroll near the bottom you will find other clues and answers part of level 157