There is a chapter on preserving fruit in The Foxfire Book I am reading. It mentions drying, using syrup and making jelly, jams and preserves. But it also gives a detailed instruction on how to Bleach Fruit!?!?!
"Bleaching: Peel and core apples; cut into quarters or eights. Fill a ten gallon wooden tub with sliced apples; then put 2 tablespoons of sufur in a saucer and strike a match and set the sulphur on fire. Cover the tub with clean cloth and let it stay all day. That night, take the sulfur saucer out. Repeat the process for 3 days. Then transfer the apples to large jars and tie clean cloths over them. You can eat them at any time of the year without any preservation."