Canning peppers in tomato sauce when they are in season lets you enjoy peppers once the season is over without paying exorbitant prices. If the peppers you will be canning are hot peppers, wear rubber or plastic gloves when handling or touching the peppers to avoid transferring the oils to your face or eyes, as it will create a burning sensation. If you really cannot stand wearing gloves, be careful to not touch your face or eyes until you have thoroughly washed your hands with strong soap and water.
Select firm, good quality peppers. If the peppers have started to go "soft", they will become mushy during the canning process.
Core and seed the peppers, cutting a small amount off the stem end. Small peppers may be left whole; larger peppers should be halved or quartered to fit easily inside the jars.
Heat the oven to 400 degrees Fahrenheit. Put the peppers on a baking sheet and bake for 6 to 8 minutes or until the skins begin to blister.
Place a cool, damp cloth over the peppers to assist in the cooling process and make them easier to peel. Once they have cooled sufficiently to handle, remove the skins. If the skins do not "slide" right off, use a paring knife to remove them.
Sterilize the jars, lids and seals by washing them in the dishwasher on the sterilize cycle. If you do not have a dishwasher put the jars in boiling water for ten minutes and the lids and seals for five minutes.
Flatten peppers and pack jars, leaving one-inch of headspace. Boil tomato sauce and pour over peppers, leaving one-inch of headspace.
Place the lids and rings on the jars. Tighten the rings.
Place the jars in your pressure canner, add the amount of liquid and set the temperature according to the directions that came with your canner. Each brand of canner has slightly different requirements, which should be closely followed to prevent spoilage.
Process the peppers in tomato sauce for 35 minutes. Remove the cans with a pair of canning tongs and allow to cool before storing.