According to Keurig, descaling
“is an important part of cleaning… This process removes calcium deposits, or scale, that can build up inside a coffee maker over time. Calcium and scale are non-toxic but left unattended, they can hinder your brewer's performance. Descaling should take place every 3 to 6 months or, for select brewers, when the descale light comes on.”
While many people choose to use vinegar for descaling since it’s all-natural and affordable, descaling solutions are specifically formulated for removing build-up, and they’re extremely effective for keeping your coffee making running reliably.