Windows can appear streaky after using Windex for a couple reasons. One common cause is the evaporation rate of the cleaner, as some window cleaners claim to be streak-free but fail to deliver unless used very specifically. If the cleaner evaporates before it gets a chance to lift the dirt away, it can leave streaks behind when wiped off. Another reason could be the presence of leftover residue from sticky contaminants, like sap. To avoid the headache of window cleaning and streaks and spots on your glass, give us a call today.