This section is from the book "Everywoman's Canning Book", by Mary B. Hughes. Also available from Amazon: Everywomans canning book; the A B C of safe home canning and preserving.
Do not can the early summer apple. It is better to use this variety as a basis for apple butter or jams. Windfall apples of the fall or winter varieties should be canned for use after the winter apple is out of the market, or when the price is prohibitive. When the apple barrels are picked over, as they should be at least twice during the winter, the apples which are specked or becoming soft may be canned.
Pare and cut out the bruised or soft spots, quarter and core, and drop into slightly salted water. Apples shrink more than most fruits, and it is well to blanch them one minute in boiling water. Plunge into cold water and pack in clean jars. Fill crevices with hot water, adjust rubber, cover, and seal lightly. Process twenty minutes.
Windfalls, seconds, or picked-over apples may be made into apple sauce the usual way. Pack hot into clean jars to one-half inch of the top, and process for ten minutes. Have the water just simmering in the hot water bath.
Store jars and use in the spring, when apples are high in price. May be used as pie filling.