In a crockpot combine tomatoes, garlic, salt, green peppers, onions, jalapeno peppers, chili powder, thyme leaves, sugar and Worcestershire sauce and mix well. Cook on low heat, covered for 8-10 hours.
Remove cover. Increase heat to high and cook 1 additional hour. Add flour, oil and vinegar and stir well to thoroughly combine for the salsa with thicken slightly.
Follow canning directions to jar the salsa and process 1/2 and 1 pint jars for 20 minutes. Makes 7 pints. Enjoy!