If you have an old microwave that is not being used why not use it to melt metal.

“Research is nearing completion on a system that will allow the melting and casting of bronze, silver, gold, and even cast iron, using an unmodified domestic microwave oven as the energy source.

To be of use for metal casting, a domestic microwave oven rated D or E (850W or 1000W) needs two slight modifications: the rotating glass plate must be removed and the holes which admit air to the cooking chamber must be taped over (masking tape works reasonably well). The air from the magnetron cooling will then be re-directed to the exterior. No other modifications should be made. Microwaves are potentially dangerous and the uninitiated should treat the oven with respect.”