1. Cut carrots and celery into 1/2 inch-long pieces. If you like, peel cucumbers; cut into 1/2 inch-thick slices. Remove seeds and membrane from red peppers; cut peppers into 1/4-inch-wide strips. Cut onions into 1/4 inch-thick slices. Cut broccoli into bite-sized flowerets.
2. In 10-quart enamel, stainless steel, or glass container, stir water and salt until salt dissolves. Add vegetables; cover and let stand in cool place about 6 hours.
3. Prepare jars and caps for processing
4. Drain vegetables; rinse with running cold water; drain thoroughly. In 8-quart Dutch oven or heavy saucepot over high heat, heat vinegar, sugar, mustard seeds, and crushed red pepper to boiling, stirring occasionally. Reduce heat to medium; cover and cook 5 minutes. Add vegetables; heat to boiling. Reduce heat to low; cover; simmer 5 minutes, stirring often.
5. With slotted spoon, spoon hot vegetables into hot jars to 1/4 inch from top. Immediately ladle hot liquid over vegetables to 1/4 inch from top (keep simmering while filling jars). Close jars as manufacturer directs. Process jars in boiling-water bath 15 minutes; cool jars and test for airtight seal