Why is it so difficult to clean windows

Cleaning and care instructions for plastic windows

support
It is advisable to support the built-in plastic windows as soon as possible, as damage can occur if plastic windows that are not supported are exposed to heavy loads.

Surface of the plastic profiles
The surface of the plastic window profiles is made in such a way that it is completely insensitive to lime and cement. On the other hand, lime and mortar splashes on fittings and glass panes should be avoided because this cannot rule out chemical burns and the surfaces of these materials can be scratched. The fittings could also block. Malfunctions in the seals are possible if residues of mortar have not been removed thoroughly.

Fittings
Should the fittings ever jam or be stiff, this can be remedied quickly and easily with a drop of oil or grease. Of course, you can easily do this yourself. For this reason, oil the fittings at least once a year to ensure that they run smoothly. Moving and rubbing metal elements need oil or grease in order to function comfortably and easily.

cleaning supplies
Because plastic window profiles have a smooth surface and are colored throughout, they are easy to clean and maintain. However, do not use coarse abrasives for cleaning. This would roughen the beautiful smooth surface. The best way to clean it is to use a light detergent solution or one of the standard soap products used in the household.