It doesn't matter if you use an office coffee maker or a home coffee maker. You should always be using a clean coffee maker. Many people say that they don't clean coffee makers because it improves the taste of their coffee. This may be true, but lack of cleaning also improves the number of germs and bacteria in your coffee. Therefore, you should clean your coffee maker well on a regular basis.
Empty the coffee and coffee grounds from the coffee maker.
Fill the coffee pot with equal parts of distilled white vinegar and water.
Pour the vinegar and water into the coffee maker and let it run through a brewing cycle. The distilled white vinegar can kill the bacteria and germs in the coffee maker.
Pour the vinegar and water out and run another cycle with just plain water.
Pour that water out and clean the pot in the sink with hot water and dish soap to remove any residue and buildup.