When cleaning your Keurig you can use vinegar instead of a Keurig descaling solution.
Although using vinegar in your Keurig could void the warranty but the vinegar will do no harm to the Keurig when used properly to clean the Keurig.
I have used vinegar in my Keurig to descale the Keurig and clean it without any issues.
I used to buy the descaling solution to descale my Keurig but at the office they just use vinegar to clean the Keurig so I started using vinegar in my Keurig at home as well.
I have been using vinegar in my regular coffee maker and so figured it would work just as great in the Keurig and it does.
Just pour some vinegar directly into the Keurig and then fill the rest with some water to dilute the vinegar.
So fill half of the Keurig with vinegar and the other half with water and the vinegar will help descale the Keurig.