How to Clean Windows Without Streaks

Scrub the glass with a few drops of dish soap in a bucket of water, pull it dry with a clean squeegee, and wipe the edges with a dry microfiber cloth. Work in the shade so the glass stays wet until you squeegee it, because cleaner that dries on the glass is what leaves most streaks.

Why windows streak

A streak is almost always something left behind on the glass. The usual causes:

Too much cleaner. Soap or glass spray left on the pane dries into a hazy film.
Cleaner that dries too fast. Sun, heat and wind dry the glass before you can squeegee it, and Treasure Valley summer afternoons are hot and dry.
Dirty or linty tools. Paper towels leave lint, and a nicked squeegee blade leaves a line on every stroke.
Dirt from the frames. Dusty frames, sills and screens drip dirt right back onto the clean pane.
Hard water. Hard water carries dissolved minerals, mostly calcium and magnesium. When it dries on glass, the minerals stay behind as white spots. Those aren’t streaks, and glass cleaner won’t remove them.

What you need

A bucket of warm water with a few drops of dish soap.
A scrubber (a window cleaner’s “mop”) or a soft sponge.
A squeegee with a sharp, smooth rubber blade. Nicked or hard rubber leaves lines, so put a fresh blade in.
Two clean microfiber cloths: one to wipe the blade, one kept dry for the edges. No paper towels.
An old towel on the sill to catch drips.

Hard tap water? Mix your bucket with distilled water, so any drips you miss leave fewer mineral spots.

How to clean windows without streaks, step by step

Pick a cool, shady time. Morning in summer, or the shady side of the house. Skip windy days, and leave the outside glass alone when it’s freezing, because the water can freeze on the pane.
Start with the frames. Take the screens out and mark which window each one came from. Brush the dust off the frames and sills, so it can’t run onto the glass later.
Scrub the whole pane. Wet the glass and work the scrubber into the corners and along the edges, where dirt hides.
Squeegee from the top down. Tilt the blade so only its edge touches the glass. Pull one stroke across the top, then pull straight down, overlapping each stroke a little so you don’t leave thin lines between them.
Wipe the blade after every stroke. Otherwise the dirty water you just pulled off goes right back on the glass.
Detail the edges. Fold a dry microfiber over one finger and run it along the edges, where the squeegee leaves a thin line of water. Then wipe the sill.
Check from an angle. Look at the pane from the side, in daylight, and buff any mark with a dry microfiber. Don’t spray more cleaner on it.

A trick for finding streaks: when you buff, go side to side on the outside and up and down on the inside. A sideways streak is on the outside, and an up-and-down one is inside.

Small windows and inside glass: the two-cloth method

For a few small panes or the glass in a door, skip the bucket. Mist a microfiber cloth (not the glass, especially near wood trim and electronics), wipe the pane, then buff it right away with a second, dry cloth.

Inside glass that streaks no matter what often has a film built up from years of glass spray. Wash it once with soapy water and a squeegee to strip that film, then go back to light cleaning.

Vinegar, glass spray or dish soap?

For a full wash with a squeegee, a few drops of dish soap in water works best. A vinegar and water mix handles light grime and fresh mineral spots, but keep it off natural stone sills, because vinegar can damage stone. Store-bought glass spray is fine for touch-ups if you use a light mist and buff it dry.

Why Treasure Valley windows are harder to keep clear

Sprinkler spots. Irrigation water hits the same lower windows all summer and dries into white mineral spots that soap and a squeegee won’t remove. Here’s how to get hard water spots off your windows.
Dust and wind. Dry summers, fields and construction coat frames and screens in dust. Clean the screens too, or the next breeze blows it back onto the glass. See screen cleaning.
Pollen and cottonwood fluff. In late spring it sticks to wet glass and screens, so waiting until it settles saves you a second round. Here’s the best time of year to clean windows in Idaho.
Winter grime. Snow, rain and gray inversion days leave glass dull and streaky, and the low winter sun shows every mark. On cold days, do the inside glass instead.

Why do my windows still streak after I clean them?

A haze over the whole pane: leftover soap or spray. Wash again with less soap, and squeegee it all off. If the glass is still cloudy after cleaning, it may not be dirt.
White dots that won’t wipe away: hard water spots, not streaks. They need a different fix.
Glass that feels rough even when it’s clean: minerals that sat on the glass for a long time can etch it, and no cleaner can bring etched glass back.

When it’s worth calling a pro

A few ground-floor windows make a fine weekend job. It’s worth calling a pro when:

Your windows are on the second story or above a slope, where the ladder is the risky part.
You have a wall of windows, or just a lot of glass.
Hard water spots won’t budge after a couple of tries.
You want the frames, sills, screens and tracks done too, not just the glass.

We clean windows by hand with a mop and squeegee, never with a pressure washer. On an exterior window cleaning, we clean the glass, frames and sills, and we take every screen off and put it back. You can add screen cleaning on our XERO machine and track detailing to the same visit.

Light hard water spots get worked on during every cleaning, and heavier spots are priced on site. Monthly and Quarterly members get hard water removal on up to 5 panes every visit at no charge, and RainBlock, our pure water rinse: water filtered down to zero minerals, so the glass dries spot-free with no soap or residue left behind for dirt to cling to. Find a streak? Tell us within 48 hours and we’ll make it right at no charge.

“I waited until the next morning to post this. I wanted to see if there were any streaks coming in the windows from the morning sun. Nothing. No streaks at all. Terence was very professional, courteous, and efficient. And his skills washing windows are impressive. …”

Le K. · Google review

Here’s what window cleaning costs in Boise. Get a free quote, or call or text (208) 484-5207, Monday through Saturday, 8am to 7pm. We clean windows in Boise, Meridian, Eagle, Nampa and across the Treasure Valley.