Dual-tone service for cleaning staff means that the cleaning staff will issue two specific passwords or inquiries during the cleaning process to ensure the smooth and efficient work. Specifically, this is common in some hotels, guesthouses or other accommodation places, aiming at providing more thoughtful and intimate room cleaning services. Before entering the guest room to start cleaning, the cleaning staff will knock on the door and shout "cleaning" or similar password to remind the guests in the room. In this way, guests can know the arrival of cleaning staff in advance and get ready. If there is no response or permission from the guests, the cleaning staff will wait for an appropriate time and then enter the room. Before entering the guest room to start cleaning, the cleaning staff will knock on the door and shout "cleaning" or similar password to remind the guests in the room. In this way, guests can know the arrival of cleaning staff in advance and get ready. If there is no response or permission from the guests, the cleaning staff will wait for an appropriate time and then enter the room. This kind of "dual-tone service" can help cleaning staff establish good communication and trust with guests, ensure the smooth progress of cleaning work and provide better accommodation experience for guests.