How do you descale a keurig coffee machine?
Begin by filling the reservoir with 10 ounces of white vinegar — or you can use Keurig's Descaling Solution. Start the brew cycle without a K-cup and let the machine run as usual, using a mug to catch the liquid. Repeat this process a second time. Then fill with fresh water and brew again.
There are commercially available products for that purpose, or you can use white vinegar. fill the reservoir a quarter way with the vinegar, and run a few cups, until the scale is removed and unit runs smooth, then rinse well and run multiple cups of water until the vinegar odor is removed.