How to can sliced pears. Prepare the canner, jars, and pears Fill a large pot or canner with enough water to cover the jars by at least one inch and bring it to a simmer. Wash jars and keep them warm to prevent cracking. You can do this by filling them with hot water or placing them in a low oven Wash and heat the lids according to the manufacturer's instructions, usually by simmering them in hot water.Peel, halve, and core the pears.To prevent browning, place the cut pears in a bowl of cool wat