How To Descale a Keurig K-Cup Coffee Maker

When the Descale light comes on remove the K-Cup coffee pod from the machine.
Replace the water in the reservoir with equal amounts of white vinegar and water.
With the machine off, press the 8 and 12 oz buttons until the center 'Start' button flashes.
With a coffee cup in place to catch the vinegar and water, press the start button.
Repeat until the 'Add Water' light comes on.
Replace the solution in the reservoir with fresh water.
Cycle the whole reservoir volume through until the Descale light goes off.
Your K-Cup Coffee Maker is now ready for the next cycle of brewing.