Ash-keys in the green state are sometimes pickled. The practice used to be more widespread, and there are many recipes in 17th- and 18th-century cookery books. That by
Ashen Keys. Gather them young, and boil them in three or four Waters to extract the bitterness; and when they feel tender, prepare a Syrup of sharp White-wine Vinegar, Sugar, and a little Water. Then boil them on a very quick Fire, and they will become a green colour, fit to be potted so soon as cold.