How to wash windows in a two-story house so that they are absolutely clean?

I know that using the right cleaners and professional window cleaning equipment will greatly increase your chances of getting excellent results and low risk to hurt yourself by washing your windows from the outside on the second floor. I also know that if you are looking for good window cleaning service in Chicago, it's best to visit this site https://cleanwindowsfirst.com/ and order their services. I'm sure they do their work well and you will get perfectly washed windows very quickly at a good price. I think this is a good deal.