Wash and peel pears. Halve and core; slice if desired. Hold prepared pears in ascorbic acid solution.
Boil drained pears 5 minutes in syrup, juice, or water.
Pack hot fruit into hot jars and cover with boiling cooking liquid, leaving 1/2-inch headspace. Add 1 tablespoon bottled lemon juice per pint or 2 tablespoons per quart. Remove bubbles, readjust headspace, wipe rims, and apply lids.
Process hot-pack pints for 20/25/30/35 minutes and quarts for 25/30/35/40 minutes at 0–1,000/1,001–3,000/3,001–6,000/above 6,000 ft.