How to Use a Crucible When Melting Metals 

First, a crucible must be seasoned before use or the metal will stick to the surface and not pour out. It should be heated slightly first before adding the metal and the metal should be clean and not dirty. Once metal is added, it needs to be heated until molten at which time a small pinch of Borax is added to prevent oxides from entering the metal. Heat until molten and pour.