Put green walnut-shells into a brine of salt and water strong enough to float an egg; let them lie covered in this ten or twelve days; take them out and lay them in the sun for a week; put them into a jar and pour boiling vinegar on them; in about a week or ten days pour off the vinegar, make it boiling hot, and pour over them again. In a month it will be fit for use, and will be found excellent to eat with cold meat, and particularly useful in making sauces.