Mold on windows is not uncommon if condensation is a problem. However, by doing some investigation work and following a few simple steps, you can easily find and rectify the cause as well as prevent it from reoccurring.
Examination - Begin the process of removing mold on windows by identifying every point where it exists. Examine the glass and frames of the windows thoroughly to make sure that you know where every instance of mold occurs. This makes it easier to remove it all at the same time. Do not overlook the inner surface of the window frames; open the windows and check inside thoroughly.