Descaling a Keurig is actually incredibly simple. No need to break out the vinegar or anything like that. Simply activate Descale Mode by holding down the “8oz” and “12oz” buttons in unison for three seconds.
The display will begin flashing, at which point you may press the “Brew” button. This will initiate Descale Mode. Place a cup underneath the spout, then dump the liquid in the sink when it’s complete. Check your manual for more information.