1. Bring canner half-full with water to a boil; simmer. Meanwhile, place 10 (8-oz.) jars in a large stockpot with water to cover; bring to a boil, and simmer. Place bands and lids in a large saucepan with water to cover; bring to a boil, and simmer. Remove hot jars 1 at a time using jar lifter.
2. Bring water, sugar, vinegar, gin, salt, mustard seeds, celery salt, dried crushed red pepper, and crushed bay leaves to a boil in a Dutch oven over medium-high heat. Add Vidalia onions, peaches, and garlic; boil, stirring occasionally, 15 minutes.
3. Pour hot mixture into hot jars, filling to 1/2 inch from top. Remove air bubbles, and wipe jar rims. Cover at once with metal lids, and screw on bands (snug but not too tight). Place jars in canning rack, and place in simmering water in canner. Add additional boiling water as needed to cover by 1 to 2 inches. Bring water to a rolling boil; boil 10 minutes. Turn off heat, and let stand 5 minutes. Remove jars from canner, and let stand at room temperature 24 hours. Test seals of jars by pressing center of each lid. If lids do not pop, jars are properly sealed. Store in a cool, dark place at room temperature up to 1 year.
Vidalia Onion & Peach Refrigerator Relish: Omit Steps 1 and 3. Prepare recipe as directed in Step 2. Let mixture cool completely (about 2 hours). Store in airtight containers in refrigerator up to 2 weeks. Hands-on time: 1 hr., 10 min.; Total time: 1 hr., 35 min.