In a stock pot, combine the tomatoes, onions, peppers, sugar and salt; simmer, uncovered, for 45 minutes.
Place the pickling spices, celery seed and mustard seed on a double thickness of cheesecloth; bring up corners of cloth and tie with string to form a bag; add to tomato mixture. Cook for 45 minutes or until very thick, stirring frequently.
Add vinegar; cook to desired thickness. Discard spice bag. Carefully ladle hot mixture into hot pint jars, leaving 1/2-in. headspace. Adjust caps. Process for 15 minutes in a boiling-water canner.
The processing time listed is for altitudes of 1,000 feet or less. For altitudes up to 3,000 feet, add 5 minutes; 6,000 feet, add 10 minutes; 8,000 feet, add 15 minutes; 10,000 feet, add 20 minutes.
Wear disposable gloves when cutting hot peppers; the oils can burn skin. Avoid touching your face.