After I posted, I did a search online and found many opinions on using Windex. Everyone who said they were told to use soap and water, had major issues with dullness, streaking and soap film. Many people use Windex, among other cleaners and the consensus seems to be if the granite is sealed properly, Windex will not harm it or dull the finish. Windex doesn't streak, nor does it leave any film or residue to dull the look. I'm sticking with my Windex. My granite is still shiny as I posted above after 4+years.