The first thing you want to do is to wash the jar you are brewing with thoroughly. Put it to air dry while you follow the remaining steps. Rinse your grains thoroughly with filtered water. Chlorinated water will kill your grains, so you don't want to use that. Once your grains have been rinsed well, put them in a bowl of water with 1/4 cup of baking soda. Mix and allow to soak for approximately 2 minutes. Then rinse thoroughly again! This process should re-balance the grains so that you have a safe batch. Use the grains to make a batch of water kefir in the clean jar as you normally would. Be sure your jar is filled almost to the top, and consider using an airlock if you aren't already!