Here is a step-by-step guide on how to can tomatoes safely and effectively:

1. Prepare your equipment:
   • Sterilize clean canning jars by placing them in a boiling water bath or simmering until ready to use.
   • Wash lids and bands in warm soapy water and set aside.
2. Prepare the tomatoes:
   • Wash tomatoes thoroughly, removing stems, blemishes, or defects.
   • Optional: Peel tomatoes by blanching briefly in boiling water, then slip off skins.
   • Cut tomatoes into large chunks or dice them to your preference.
3. Fill the jars:
   • Pack tomatoes tightly into sterilized jars, using a funnel for ease.
   • Add 1 tablespoon bottled lemon juice or 1/4 teaspoon citric acid per pint jar (16 oz), or 2 tablespoons lemon juice per quart jar (32 oz) to ensure safety and acidity.
   • Add salt if desired (usually 1/2 tsp per pint and 1 tsp per quart).
   • Leave about 1/2 inch of headspace at the top.
   • Wipe jar rims clean of any tomato residue for a good seal.
4. Seal and process:
   • Place lids on jars and screw on bands fingertip tight.
   • Process jars in a boiling water bath canner:
     • For pints, process for 40 minutes.
     • For quarts, process for 45 minutes.
     • Adjust processing time for altitude if necessary.
   • Alternatively, pressure canning can be done at 10 PSI for 15 minutes (pints) or 20 minutes (quarts).
5. After processing:
   • Remove jars with a jar lifter and place on a towel or padded surface.
   • Leave jars undisturbed for 12 to 24 hours to cool and seal.
   • Check seals by pressing the center of the lid; it should be concave and not pop back.
   • Remove the bands and store sealed jars in a cool, dark place. Use within 12 to 18 months for best quality.

This method ensures your canned tomatoes are safe, shelf-stable, and ready for use in recipes throughout the year.