Contact one of the Banco de Portugal’s cash offices (or a cash office of another Eurosystem national central bank), which will check the banknote. If doubts remain as to whether the banknote was intentionally mutilated or damaged, you must identify and explain in writing the cause of the mutilation or damage or what happened to the missing parts of the banknote. If the banknote has ink stains or is dirty, you must also give a written explanation of the circumstances in which this occurred.