Using your oven to sterilize jars you use for canning is an effective and efficient way to prevent the growth of harmful mold and bacteria in any food you choose to can. Not only does it protect the people eating your food from potential foodborne illness, but it also protects the fine flavor and texture of your special recipes.
Preheat your oven to 225 degrees Fahrenheit. Make sure to adjust the oven racks to accommodate the jar's height.
Arrange your jars, lids, and bands on the cookie sheets. Leave space between them for the hot air to circulate. If you're reusing Mason jars from previous years, remove the lids and bands from those jars so that everything is open and separated before you put your equipment in the oven.
Place the cookie sheets with your jars, lids, and bands on them in your preheated oven. Set a timer for 10 minutes, and do not remove anything or open the oven door before these 10 minutes have elapsed. If more than 10 minutes elapses, that's OK, but 10 minutes at that temperature is all you need.
Turn the oven off and leave the jars, lids, and bands in the oven to keep them warm until you're ready to use them for canning. Although 225 degrees is a comparatively low oven temperature, always use oven mitts or thick hand towels to handle anything you take out of your oven.