Gather the necessary cleaning supplies: You'll need a bucket, a squeegee, a scrubber or sponge, a microfiber cloth, a mild detergent, and water.
Prepare the cleaning solution: Mix a small amount of mild detergent with warm water in the bucket.
Scrub the window: Use the scrubber or sponge to apply the cleaning solution to the window, working from top to bottom. Be sure to clean the edges and corners of the window as well.
Squeegee the window: Use the squeegee to remove the cleaning solution from the window, starting at the top and working your way down. Be sure to wipe the squeegee blade with a clean cloth after each pass.
Dry the window: Use the microfiber cloth to wipe any remaining water from the window and to dry the edges and corners of the window.
Repeat as necessary: If the window is particularly dirty, you may need to repeat the process several times to achieve a clean, streak-free finish.