You want the water in all bottles brought to a sustained steaming boil. Start your brewing sometime in the evening. It takes about 45 minutes for 2 gallons of distilled water to reach a boil. Stir in the herb mix and when it starts to simmer again, put the lid on. During the reheat, prepare your bottles.
Dish detergents create bubbles which are too hard to rinse away.
Wash the caps with the antibacterial kitchen cleaner too. Give each bottle a good shake and swab the insides with a bottle brush. Set each bottle under running hot water faucet until overflow runs clear, then pour water out. Microwave bottles for 15 - 20 minutes to steam sterilize. Afterward let the microwave door stand open for a few minutes .