Put simply, over this way bread comes in plastic bags, with small squares of plastic (see Exhibit A below) to seal the bag. Within 1 trillionth of a second of taking it off the bag, it is impossible to find.
So, I devised a prototype, a tinfoil hat covered with the little plastic squares.
Initial
trials were not entirely successful as I can't find the hat again, it's here somewhere (rummages down the back of the futon..)