wow, never even heard of them. . .kind of reminds me of that silver looking paper wrap/shell(think hot pockets) that is supposed to make things crispy in a microwave, never really does the trick, but no harm in trying. . .
Also, how is that bag going to stop all the melting cheese from running of the bottom?
If I want a grilled cheese, it takes just as long to heat a pan over the burner as a toaster would take, so Imma stick with the tried and true.