Chewing or biting the stopper can cause its deformation and result in leakage. The stopper/nozzle is provided with a convenient OPEN/CLOSE system. Pull the stopper/nozzle strongly upwards in an OPEN position to remove it and push in a new one.
It is a possibility to purchase a whole new lid/stopper set in different colours in case of damage. The set includes a lid, a stopper and a sealing ring.
Long term usage can eventually cause a moderate wear of the elastic sealing ring. If you notice any leakage you should replace the sealing ring to restore its original functionality.
To remove the sealing ring from the lid you should use a thin tool to pull the seal out. Insert the new seal with the help of a knife or the end of a tea spoon. Once the lid is screwed on the seal will settle in the correct place. Your bottle is now ready to be used.