Peel tomatoes, then chop into small pieces. Chop celery, onions, and peppers into fine pieces. Mix together the vegetables and salt. Place in refrigerator overnight. Drain thoroughly in the morning. Combine sugar, spices and vinegar, making sure the sugar is dissolved, in a large saucepan. Bring to a boil and simmer 3 minutes. Add vegetables and return to a boil. Simmer for 10 more minutes, stirring occasionally. Remove cheesecloth bag holding mustard seeds. Spoon into hot sterilized jars and seal.