Your home coffee maker needs to be periodically cleaned, literally, from the inside out. The good news is that it's pretty simple. If you have hard water, mineral deposits can build up inside, but all you need is white vinegar to clean it out. Pour about 1 quart white vinegar where you normally put cold water to brew your pot of coffee. Wait two hours. The natural acids in the vinegar will break down the mineral deposits. Then brew as normal, allowing the white vinegar to run through the whole coffee maker. Finally, run a whole pot of fresh water through to remove any traces of vinegar.