A reader (who is clearly not alone) asks: What causes some sliced deli meats to possess an iridescent sheen? On occasion, a slice of ham or beef will exhibit the sort of rainbow spot one might see ...

In the 1947 film noir Out of the Past, starring Kirk Douglas as a mobster and Robert Mitchum as a private eye, the server at a small town lunch counter ... of slices of boiled ham off a towering ...