Wie entfernt man Kalkablagerungen vom Badezimmerboden, die mehrere Jahre nicht gereinigt wurden und sich zu einer harten Schicht entwickelt haben?

Essig or Essigreiniger, you can clean anything related to Kalk with vinegar. I would say put the vinegar dissolved in some water on the surface, let it react to the Kalk and clean.

tart by gathering the following: an acidic cleaner like vinegar, an alkaline cleaner, and an electric brush.

Begin by applying the acidic cleaner, followed by a rinse with clear water. Afterward, use the alkaline cleaner.

Think of the layers on your floor as a mix of limescale and soap, possibly built up in multiple layers. To effectively clean the floor, you need to remove these layers one at a time: the acidic cleaner (vinegar) will tackle the limescale, while the alkaline cleaner will remove the soap.