Those things are f*cking lethal. My mate served me up a bean and cheese toastie he'd made in his. The first bite filled my mouth with a substance slightly hotter than lava. The inside of my mouth took some time to recover.
What did you expect from something straight out of a HOT toastie-maker ?? A nice cool sandwich ??
Of course, I've never been known to do that ... Melted cheese doesn't half burn .. err ... someone's mouth