I used to visit Ilford Photochemical as a contractor, at lunch there was a canteen regular who melted portion size butter wraps on a plate in one of the microwaves, 2.7kW input. He would stand close to look through the window in order to monitor the "doneness" and his face would be lit up by the activity inside the cooking chamber. It was in Cheshire, "strong in arm...".create quite impressive arcing, especially if it's aluminium foil.