Place garlic cloves in a medium bowl, first cutting the large cloves in half. Mix in the red bell pepper.
In a large saucepan over medium high heat, place the distilled white vinegar and white sugar. Wrap ground dry mustard and celery seed in a spice bag, and place in the liquid mixture. Bring to a boil. Boil 5 minutes. Stir in garlic and pepper. Continue boiling 5 minutes. Remove from heat and discard spice bag.
Place garlic and peppers in sterile containers to within 1 inch of the top. Fill with remaining liquid to within 1/4 inch from the top. Seal and store in the refrigerator approximately three weeks before serving.