Coffee Maker About once a month, clean the buildup inside the machine with a commercial coffeemaker cleaner (to prevent pipe blockage). Or pour equal parts white vinegar and water (two cups of each) into the tank. With the carafe in position, run the machine for half a cycle, then switch it off. After an hour, turn it back on, and let the rest of the solution filter through. Run two or three cycles with fresh water before brewing coffee.