The fastest way to properly descale a Keurig brewer is to clean it with Keurig descaling solution. Water, a timer and a large coffee mug are also needed. The entire process will take about 45 minutes.
Make sure the machine is off. Start the cleaning process by removing the water filter and emptying the water from the reservoir. Next, pour the entire bottle of descaling solution into the reservoir, then refill the bottle with water and pour it into the reservoir as well. Then, place the coffee mug onto the drip tray, select the largest brew size and run a cleansing brew. Discard the contents of the mug when brewing is finished.
Continue to run cleansing brews until the machine indicates to add water. Next, leave the machine on and let it sit for at least 30 minutes. Discard any remaining liquid in the reservoir and rinse it thoroughly. The final step is to rinse the Keurig with fresh water to make sure all of the descaling solution is discarded.
To do this, fill the reservoir with clean water. Place a large coffee mug on the drip tray and select the largest brew size. Run a minimum of 12 clean water brews to ensure the machine is properly rinsed. Finally, replace the water filter and brew coffee as desired.