Now that the temperature outside has dropped, the windows start to accumulate water vapor. I am assuming that it might also lead to that black stuff forming. Is there a more efficient way of dealing with the condensate than wiping it dry every day?
If you cannot afford to replace the windows then look into adding storm windows. This is simply another window added to the outside of your window that adds another layer of insulation. Usually this increases the insulation enough to stop condensation.
These are common in the US. IDK how common they are in Europe.