Green Tomato Relish

Combine green tomatoes, onion, bell pepper and salt in a medium nonreactive saucepan. Stir in vinegar, sugar, mustard and celery seeds. Bring the mixture to a gentle boil over medium heat. Reduce heat to low and simmer, stirring occasionally, until the tomatoes, onions and bell peppers are very tender, about 15 minutes. Stir in cloves. Transfer the relish to a medium nonreactive bowl or divide among 2 pint-size mason jars. Refrigerate, uncovered, to chill completely, about 30 minutes. Serve chilled or cover and refrigerate for up to 2 weeks.