Please read About Making Preserves and How to Process.

Scrub:

Peel, core, and cut them into eighths, reserving the fruit, and put the peels in a pan with just enough water to cover. For each 1 quart water, add:

Simmer until the peels are soft. Strain the liquid through a fine-mesh sieve into a wide, heavy pot. Weigh the quince slices and add them. Weigh the same quantity of:

Bring the quince slices to a boil and add the sugar. Return to a boil, then reduce the heat and simmer until the fruit is tender. Plump overnight.

Prepare a water-bath canner, gather all your canning equipment, and have ready clean, hot half-pint jars. Return the preserves to a boil. With a slotted spoon, pack the fruit into prepared jars. Continue to reduce the syrup until it bubbles thickly. Cover the fruit with the reduced syrup, leaving ¼ inch headspace. Wipe the rims. Place lids on jars and screw on rings until fingertip-tight. Process for 10 minutes. Let cool completely and store as directed.