I know this is a joke but just for safety's sake, I want to mention that this would be a bad idea in a modern toaster. The grates close, covering them in melted cheese, and now you have either a ruined toaster or a fire hazard on your hands.

I remember when this image was making the internet rounds a couple years ago and I was surprised how many people hadn't thought about the issues with it. Luckily, I know no one that had tried it for real.