Cleaning the glass parts

The best way to clean the top part is with a glass cloth and glass cleaner. Polish the glass with the glass cloth until you are satisfied.
Clean the bottom glass part with a soft (dish)brush and and some dish soap. When you are done, rinse the reservoir with water.

If there is water scale in the water reservoir, it can be removed with water softener. Then, polish the glass with dish soap and rinse it afterwards with water, so that all the chemicals are removed.

Do not use other chemicals while cleaning the glass.