If you really like frothed milk beverages and coffee additions, you can invest in other tools that will warm milk without rotting your coffeemaker from the inside out.
For example, the Keurig Cafe One-Touch Milk Frother is an ideal tool for warming milk and is easy to empty fully and clean.
SEE ALSO: Can You Microwave Milk?
The Limitations of Milk
Of course, one of the handiest things about a Keurig coffee maker is that you can leave water standing in it for the next brew. Milk, unfortunately, doesn't tolerate being left at room temperature for a long time and will spoil.
You will need to add fresh, cold milk to whatever warming tool you use prior to frothing or heating your milk and not in your Keurig's water reservoir.
Too Late! I Added Milk To The Reservoir
If someone has already tried to make the perfect latte or hot cocoa by adding milk to the water reservoir, you'll need to get out your manual and take the coffeemaker apart to get all of the liquid out of it.
Cleaning a Keurig by running repeated cups of hot water through the tool will dilute the milk, but you need to empty it fully and replace any filters you find before putting it back together.
Burning vs Spoiling
If you notice a strong odor immediately following the addition of milk to your Keurig, be aware that that odor comes from burning, not from spoiling.
Burned milk can often be taken up with steel wool on external surfaces, but it may not be possible to access the internal components of your Keurig.
Your Keurig reservoir is extremely useful in rapidly brewing a great cup of personalized coffee, but milk is not a great addition.
Consider investing in a water filtration pitcher or a spot in the refrigerator for Keurig water to remind everyone in your household and office that water is the only liquid to be run through the Keurig!