Some of the machines come with a self-cleaning function. This can be a great way to stay on top of oil build-ups. You should do this regularly if your machine allows for it. But even with this feature, it is a good idea to deep clean your coffee maker once a month. You can flush the machine with diluted vinegar or citric acid powder, preventing mold and limescale. Whichever method you go for, flush your machine thoroughly with water before you brew again.