Listerine Coolmint mouthwash 500ml. Brushing only cleans 60% of the surfaces of your teeth leaving plaque bacteria to grow in the hard to reach places in your mouth. Used twice a day Listerine Coolmint is proven to: 1. Kills up to 97% of germs left behind after brushing. 2. Reduce plaque by up to 56% more than brushing alone. 3. Provide fresh breath protection for up to 24 hours. 4. Maintains healthy gums by killing germs above and below the gum line to keep gums healthy.