Pro cleaners reveal the simple, streak‑free method for washing windows—and the common mistakes that make them look worse.

Cleaning the windows on your home, on at least a seasonal or semi-annual schedule, is an important part of homeownership that will help your windows last longer and keep your home looking its best.

Dear James: My new house has many windows and I have a problem cleaning them without leaving streaks, especially on the south-facing ones. How do professionals clean them? — Alex J. Dear Alex: You ...