Gather green nuts in early summer when sufficiently developed to pass a pin all the way through them. Make a brine of 3/4 cup salt to each quart of hot water. Let cool; pour over nuts; let stand 24 hours. Drain; cover with fresh brine; let stand 2 days; drain and rinse. Place in sun, turning over frequently until they are black. Heat sufficient vinegar to boiling point to cover walnuts. Add 1/2 cup white sugar, 2 tablespoons each mustard seed, cloves, peppercorns, mace and broken cinnamon to each quart of vinegar. Pack the nuts in jars, pour over hot vinegar mixture. Seal. Walnuts should be sufficiently pickled to use in 4 to 5 days. Note: Pickling requires nuts too young to have begun forming the shell, which would be unpalatable in a pickle. The test described is to take nuts as large as possible, while still able to pass a hatpin through - before the hard shell begins to form inside. May or June at the latest probably.