Your Plum keeps track of when it needs cleaning of the wine circuit. While there are no health risks, it ensures that a wine with a flaw such as Brettanomyces does not affect your next bottle. When the system needs cleaning, every 120 days or 25 wine bottles, it will notify you on the touchscreen and walk you through the process. You can also run this protocol by going into Settings > General > Clean and selecting the correct side.
Use the included white cleaning bottle and fill it first halfway with hot tap water (important: use water above 120° Fahrenheit / 50°Celsius but do not exceed 140° Fahrenheit / 60° Celsius). Add the contents of a cleaning packet, then vigorously shake for 30 seconds. Continue filling the bottle up into the neck then and insert the bottle into the Plum on the side that Clean has been selected to run on. Follow the instruction on the screen. Your Plum will prompt you when you need to put a container under the spout during cleaning.
You will also need to follow the last steps of wiping out the area under the needle doors, as condensation from the thermoelectric cooling system will build up there.