You may have seen Tom Cruise scale the massive skyscraper in Mission Impossible, Burj Khalifa stands at a whopping 2,717 feet tall and hosting 24,830 windows for a total of 1,292,500 square feet of glass — all that had to be cleaned. To save on cost, the windows were cleaned using soap and water — no special chemicals.
As a sidenote, you can see Burj Khalifa — along with the top 25 tallest buildings in the world — in the youtube video produced by my nine-year-old son Ethan. (I had to brag on him. Sorry!) Thanks for watching!