Combine the tomatoes, vinegar, sugar, onions, celery, bell peppers, salt, cinnamon, ginger, and mustard seeds in a large saucepan.
Bring to a boil, stirring to dissolve the sugar. Decrease the heat and simmer for 2 hours, until the sauce cooks down and thickens. Stir frequently to prevent scorching.
Pack the mixture into clean hot 1 pint canning jars, leaving 1/2 inch headspace. Remove any air bubbles, wipe rims and add hot lids/rings.
Process in a boiling water bath canner for 15 minutes.
Makes 4 to 6 pints