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Window Cleaning Techniques

Practice is the key to success. Handling a squeegee feels awkward at first, as does any new skill, but it doesn’t take long to become comfortable and confident. Don’t be discouraged that you can’t master squeegeeing after a few days. Technique is the key to streakless, clean windows achieved in minutes. Preparation

When you arrive at the first account of the day, put on your apron; put a small cloth and sponge in the left and right hand pockets. Make sure you have a good single-edge razor blade in the center pocket; the squeegee, with a good, sharp edge, in the right hand holder; and a large towel over your left shoulder. The strip washer should be in the bucket. If you use a chamois, soak it and wring it to properly dampen it.

Put a small amount of cleaner (3 or 4 squirts) in the bucket (2 1/2 gallons of water in a 5 gallon bucket). Half fill the bucket with warm water if possible, and change it regularly to help prevent streaking.

Where To Begin

If ladders are necessary, set them in place. Normally, I started on the outside because I liked to get the hardest part over with first. During the winter I started my day on the inside until the weather got warmer. During the summer, if I could, I arranged my day so that I was not washing windows on the sunny side or was not staring into the sun.

When beginning on the outside, do the highest windows or the hardest ones first to get those out of the way. To work efficiently, determine a starting point and then work around the house or building, carrying the bucket and step-stool or pole, if necessary. Keeping all your tools with you makes trips to the car unnecessary. Always start with upper windows as you will be dripping on the lower ones. Use the same procedure for the inside windows.

It’s very important to protect woodwork and floor on the inside of homes and buildings. Use less water on the inside windows, catching spills with a towel on the floor or sills. If the woodwork around windows gets wet, wipe it off immediately. Lay towels on the floor under the windows to catch water.


For actual window cleaning, first determine if the entire window needs scraping. Experience will tell you. I didnít normally totally scrape unless it was unusually dirty or new. If it does need scraping, inform the customer of its need and the additional charge.

Before scraping, be sure to determine whether or not there is any type of tinting film or coating on the window which a blade might destroy. Also determine if the glass is tempered. This type of glass will often have a blemished surface caused by tiny particles not washed off before the glass was placed in the tempering oven. These microscopic “pimples” can break off under the blade and then scrape the glass as you push them along.

For thorough scraping, use the four or six inch blade. Razor blades can scratch glass, so make sure that you have a new blade in the holder to start and check the blade often to make sure there aren’t any burrs that have developed on the blade edge which will scratch the window. Turn a double-edged blade over in the holder to a fresh side. If you’re doing a large job, you’ll have to change the blades often–maybe several times before youíre done.

Next, wet the strip washer with water from the bucket, and thoroughly wet the window. If you’re on the inside, slightly squeeze the excess water out of each end of the strip washer with your hand. Another technique is to let it drip for a few seconds, holding one end down, then flip it over and wash the window–no drips! Always thoroughly wet the glass before and during scraping and be sure you reach the edges and corners. Scrape the glass being careful not to damage the casing at the edges with the blade–or damage the blade with the casing! Scrape the windows in a one-way motion, not back and forth. If you drag the blade back, it tends to pick up grit which can scratch the glass. Also, beware of using the four inch blade on the end of the extension pole. Make sure the blade is flat against the glass; itís easy to scratch with the ends. Make sure that the blade is retracted or is in its safety cover between uses. Cuts that require stitches are no fun!

An alternate scraping tool, preferred by some window cleaners, is the broad knife, usually a six inch sheet rock taping knife kept very sharp–sharpened up to twice daily with a file. Note–keep rust off the blades of both razor scrapers and broad knives, for rust can easily scratch glass.

This would be an appropriate time to mention CONSTRUCTION CLEANING, a specialized area of window cleaning which consists of cleaning the windows of newly built homes and buildings. It involves a thorough and often difficult scraping of windows to remove paint splashes, plaster overspray, caulking, mortar and the general heavy duty dirt and grime left over by the act of construction. This work is extremely difficult and requires particular knowledge and expertise not only to remove the various substances but to avoid damaging the glass while doing so. Because of this, construction cleaning should probably be a full-time specialty, and not an add-on opportunity to regular window cleaning. It can, however, be lucrative, often earning up to three times as much as normal window cleaning–if you are proficient you may get from $250–$450 per house/building.

Construction Clean-up Procedure:

  1. Thoroughly examine the job, window by window. Point out any pre-existing scratches or damage or you will surely be blamed later. Also indicate any particularly difficult areas that may cause problems. It is important that you establish right from the start just what your responsibilities and liabilities are.
  2. Vacuum or brush off all frames and sills to get rid of excess debris–this keeps your water clean longer and gets rid of many potentially scraping particles.
  3. With soapy water and a rough pad or brush, clean all frames.
  4. Wet the glass thoroughly and scrape it–edges first, then interior area.
  5. Wash the window, with a brush and soapy water and then squeegee per usual.

Beware of using a strip washer for construction clean up–grit can become trapped in the fibers and then scratch the glass. Use only high-quality brushes.

For some substances, very fine steel wool 000 to 0000 in grade can be used, as well as various types of emollients and solvents, but always test test test, and be confident you know what you are doing before running the risk of damaging a window that you will then be expected to replace.


If scraping isn’t necessary, wet the glass with the strip washer (or sponge or brush if you’re washing small panes) and using the small blade, scrape adhesive tape, if there is any, off the glass. Tape comes off easily with a razor when wet but smears on the window when dry. Scrub with the rough side of the strip washer, or a separate white pad, to remove anything else that’s stubborn. Place the strip washer in the left hand carrier of the apron or drop it into the bucket.

Squeegee Technique:

With the squeegee in the right hand (if you’re right handed of course) and a small cloth or sponge in the left, “cut” the very top of the pane with the corner of the squeegee to leave a small dry strip at the top edge. To do this, tilt the squeegee and press about one inch of one end against the glass and pull the squeegee horizontally across the top of the window. This helps to prevent streaks by not pulling down water from the top edge with your squeegee.

Wipe the squeegee edge dry with the small cloth, chamois or sponge as per your preference–but don’t worry about getting the squeegee blade bone dry. A slightly damp blade will slide better than a dry one, which can skip and jump.

Start with the right side of the window, if you’re right handed, holding the squeegee by the handle at a 45-degree angle. Pull down in a continuous motion from top to bottom, or as far down the window as you can reach, without pressing too hard. (A light stroke is enough–don’t wear out your arm, a mistake enthusiastic rookies often make. Let the squeegee blade do the work!) Repeat the motion across the glass, overlapping the right edge of the squeegee in the dry area already done, by an inch or two to prevent wet lines down the center of the glass. Tilt the squeegee slightly diagonal, downward towards the wet area, to keep the water away from the cleaned area. If the window is too large to continue one motion from top to bottom, or if the sill at the bottom prevents you from ending at the bottom, then leave off where it’s comfortable. Then complete the window by going across the bottom from side to side, “cutting” your final pass similar to step one.

Wipe the bottom sill and edges and any missed spots on the glass.

If the window is wider than it is long, then clean the entire window from side to side, first “cutting” the glass with the starting edge. Get the most efficiency out of your movements.

If the situation permits, squeegee the inside with top-to-bottom strokes and the outside with side-to-side strokes, or vice versa. If any streaks appear, you’ll know which side of the glass they’re on.

When moving from side to side, if the window frame prevents you from going all the way to the other edge without damaging your hand, then reverse the procedure first described, by working from one side to almost the other, all the way down the glass, then finishing with a top-to-bottom stroke on the one side. Or, as you approach the right side, twist the blade with your wrist so the right edge touches the vertical molding and then complete the downward stroke to the bottom of the window.

Another method is by making the twist at the edge that brings the squeegee down and ends with the final stroke on the bottom. Then bring the squeegee in from each side, meeting in one wet line, squeegee length, that you can then dry with a chamois or towel.

As you become more proficient with the squeegee, you can move on to learning a more advanced and efficient technique (the one the “pros” use) known as “fanning” or “snaking.” With this method, the squeegee never leaves the glass for the entire window. Start the squeegee at the top left of the glass (after “cutting” the edge), bring it across, make the bend at the top right corner and continue down the glass, turning at the edges. It should be one continuous swinging motion and you’ll be rotating your wrist to make the turns. Your hand always remains the same distance from the window. At first it sometimes leaves at the turns little triangles of wet glass that need to be dried, but as you practice it will get easier. Once you’ve mastered this technique, you’ll be able to work very rapidly which translates into more dollars for you. Again, try it out and keep practicing. Even the “pros” started with learning the basic technique. You will master it as well.

Squeegee Tips:


  • Turn the blades over when one side becomes worn. Always install the new blade with the manufacturer’s name showing on top, and that way you will know if you have yet flipped a blade. (The same can apply to razor scrapers!)
  • Some cleaners cut a small 45 notch, or triangle, off the ends of the blades so that they don’t rub up against the side of the glass, especially if there is a lot of window seal which lifts the blade off the edge of the glass and leaves moisture behind.
  • Investigate the possibility of re-sharpening your blades when they are worn. There are blade-sharpening tools made especially for this.


If you’re using the pole on large plate glass store front windows put the wet strip washer on the end of the pole. If the window requires the extension pole, first measure it against the window to determine the proper length. Wet the window almost to the top of the glass, being careful not to wet the top window frame. Use a horizontal motion for the top and then up and down vertical motions for the rest of the glass. Scrub the glass, if it is excessively dirty, with the rough side of the strip washer, and wet thoroughly.

Starting at the right side, if you’re right handed, place the squeegee, on the end of the pole, at the top of the glass. Bring it down the pane, in a slightly diagonal direction, either to the bottom of the window, if it’s above your head, or to shoulder level. I found wiping the blade between each motion with the small cloth or sponge the most effective method, unless the pole is extended, even though it took longer. Other window cleaners use only a wet squeegee in these situations, tapping it on the still-wet part of the glass before the next sweep. Try it out and see what method you find the most effective. Place the squeegee at the top of the glass again, overlapping the first stroke about 2 inches. Tilt the blade slightly toward the remaining wet portion to prevent dripping on the area already cleaned.

If you’re able to reach the bottom portion of the window, remove the squeegee from the pole and finish the window by hand. Place the squeegee at the left side of the molding and pull across the glass to the opposite side. If a window frame or molding prevents you from finishing at the edge, turn the squeegee at an angle to finish the motion at the bottom of the glass. If you’re working on the inside, hold the strip washer or a sponge under the end of the squeegee to catch excess water.

After the window is squeegeed, place a clean damp cloth or chamois on the end of the pole, or held in a clamp, and run along the upper edge and sides of the window. Wipe the edges by hand as far as you can reach. Wiping edges prevents streaks, giving a professional finish to the job.

Squeegees with adjustable-angle handles make it easy to use the squeegee and strip washer on “A Frame” windows or windows with unusual angles, when attached to a pole. The squeegee and strip washer swivel on the handle to adjust to various angles and make it possible to use a pole on windows that ordinarily couldnít be reached because of height or distance.

Using a water-fed extension pole is a similar procedure. Work, of course, from top to bottom. Always raise the upper sections of the pole first, until you have reached the desired height. Use side to side strokes across the top of the window, then up and down strokes for the rest until reaching the bottom, when you move the brush back and forth again. Make sure the brush gets well into all four corners. Washing the frames while you wash the windows will actually keep the windows clean longer, because rain will not wash frame dirt back onto the glass. Be especially sure to wash flat aluminum frames, for they are much more likely to get wet during rinsing and if dirty will re-soil the glass.

When rinsing, avoid spraying the water above the top frame, on the wall itself, for it will only drip back later and make streaks. Rinse with side to side motions over the entire window, rinsing slowly and thoroughly.

Avoid getting wash or rinse water on rough, unsealed wood frames, which will hold the water then release it after you have moved on, to leave streaks.

Note–a water-fed extension pole system will not be effective for construction clean up.


After the window is dry from the squeegee, use a clean damp lint-free towel or chamois to dry off the top, bottom and side edges. Wrap the towel over a couple of fingers and hold the rest of it off the glass. Mop the excess water off the bottom with another towel or sponge. I’ve seen professional window cleaners in cities doing large windows who don’t bother drying the edges. In my experience, it makes a big difference. My business was successful because I was careful, meticulous and I left the windows clean.

I’ve since heard of a good trick for wringing out towels or chamois without having to wear out your wrists and forearms, since you have to do this action many times a day. Fold the towel/chamois around the bucket handle (with water in the bucket), grab the two towel ends together in one hand, and then with your other hand give the bucket a good spin. The bucket’s weight and spin will wring the cloth for you!

Stains/Special Problems

One frequent problem you will encounter is nicotine, particularly in restaurants and bars and the homes of heavy smokers. The best thing I know to cut through smoke film is industrial strength window cleaner. It can take at least two washings with the strip washer–and sometimes even scraping–to cut through the film. If you don’t cut through all the way to the glass, you’ll be leaving a lot of streaks. You’ll recognize nicotine; it washes off a brown color, and the strip washer drags across the window.

Another common difficulty is mineral spots from hard water. Although there are solutions made just for this, like MDR, the best solution is prevention. I advise customers to avoid sprinkling their windows when watering their lawns. Or if they do get water on their windows, to squeegee it off before it dries. Mineral spots are difficult to remove. Steel wool (000–0000) is a good choice to start with. If this doesn’t work with soapy water (it should only be used wet), try applying straight vinegar with the steel wool. Jeweler’s cleaner or pumice is one solution that many window cleaners have luck with, but you should try it in an inconspicuous place first.

For various kinds of grease on glass, rather than using a lot of chemicals, which create residue and more difficult detailing, you might try just a mildly soapy solution and then a razor scraper.

I occasionally ran into windows that had been sprayed or treated with a sun screen plastic coating or window tint. These can be washed normally, but at all costs avoid contact with a razor blade, or anything abrasive (brush, cleanser, steel wool, etc.). A cloth or sponge is a good choice for cleaning these sensitive windows. Use lots of water when cleaning these–perhaps even hose the window down thoroughly before actual cleaning, to remove grit that might scratch beneath the strip washer, cloth, sponge or brush.

Crystal Clear 550 for Glass Restoration is also recommended to remove hard water marks, exhaust from car and aircraft, run-off from unsealed masonry, airborne pollution, acid rain and just about anything that has caused oxidation of the glass. Itís easy to apply with a cloth or natural sponge and a little goes a long way. Again, make a test application in an inconspicuous area of the glass to determine effectiveness and suitability for each specific job; and protect your skin and eyes from the chemical with gloves and goggles.

Here is advice on some more stains/problems you might encounter:

Silicone sealants–spray or wipe on denatured alcohol, let it dwell a bit, then scrape off. Or, try OilFlo on a white pad.

Adhesive tape–First, just try a razor scraping with soapy water. If it persists, there are several products you might try: OilFlo, Citrus-Solve, De-Solv-It, Lift-it. Check with a janitorial supply or hardware store. Also, POG solvents and degreasers such as carpet cleaners like Grease Release.

Holiday Paint, Snow, Advertising paint, etc.–If it is water soluble, wet the surface well with strip washer then scrape the paint off–scraping it into large globs which are then dumped into a bucket or bag. Then wash the window as usual. Any missed spots can be scraped or removed with ultra-fine steel wool. A degreaser can work well on spray snow–apply it directly to the strip washer, then scrape if needed. If the paint is quite stubborn or not water soluble, try a gel type paint remover. Smear it on (wear gloves for this), let it dwell a bit, then scrape with a razor scraper. Wash the window.

Wood Sealant/Deck Treatment Overspray–some will come off with a hard-water, acid rain, or mineral deposit remover. Acetone may also be effective, but you might have to try a de-etching compound, like Unger Rub-Out.

Putty, Tars, Caulking, Glues, etc.–OilFlo, or a brand of citrus solvent.

Tree sap–mineral deposit remover, OilFlo, lacquer thinner, or commercial tar removers such as “Goo Gone” found in auto parts stores.

“Screen Burn”–windows with aluminum screens in front of them will often show a type of etching or stain. Sometimes this is simply mineral deposits from hard water or rain, but it may also be an actual aluminum oxide buildup called screen burn. Window cleaners offer several possible solutions–try each first in an inconspicuous place and decide for yourself. Some praised the use of an off the counter retail oven cleaner, but be very careful. Wear gloves and do not let it stay on the glass too long. Oven cleaners contain hydrofluoric acid which can eventually eat away at the glass itself. Use glasses or goggles and even a respirator if need be, for any long exposure to such fumes can burn your lungs. Other vehicles for hydrofluoric acid come labeled as pool cleaners.

Look for products called “Zud” or CLR, suggested by several window cleaners, for they are said to be safer than hydrofluoric acids.


Sometimes a customer removed screens in advance of my arrival, but normally I did that myself. If there were cobwebs on the screens, I dusted them off, but I didn’t do any special cleaning of screens unless specifically asked to do so, and then I charged extra for the cleaning. If the screens are left dirty or dusty, however, the window will get dirty much sooner and the customers won’t be able to see clearly. You might try advertising screen cleaning as an extra service to increase your business.


Another problem area is sky lights that need cleaning. Plexiglas scratches very easily so you can’t use anything even mildly abrasive. Even a soiled terry cloth towel could cause scratches. Use only clean, fresh water and some non-sudsing mild detergent. Normally if tape has been allowed to remain on Plexiglas for some time it is almost impossible to remove–you might try Dilomere, or a product called “Lift Off”. If the Plexiglas has any kind of adhesive on it, try rubbing on some Vaseline with your fingers and rolling the adhesive into a ball. Follow the Vaseline with Milk of Magnesia as a cleaner. I never tried this method but it is used for cleaning the canopy covers of jet airplanes. My method? “I don’t clean skylights.”

For flat Plexiglas windows or doors, the same cautions apply. Wash them with a clean strip washer and dry with the squeegee or very soft cloth towel. The fabric of the strip washer won’t cause scratches as long as it and your water are clean.

Storm Windows

Doing storm windows takes much longer because you’re essentially washing two sets of windows, so charge accordingly. If the storm windows are attached to the inside, remove and set the removable portion on the floor on a towel to catch the drips and wash the inside portion while it is in that position. Then wash the inside part of the stationary glass. Dry the inside sill and tracks as much as possible. Replace the window, making sure it’s thoroughly dry. Then wash the window inside and out as usual. Be very careful in handling these, as the frames are sometimes not secured to the glass. I broke my first window in a mobile home because I was holding the metal frame on the sides and the glass slid out the bottom. Support the window from top to bottom.

No matter how much you dry the window and the inside sill, there is still bound to be moisture that will fog the glass once they are back together. Explain to the customer that the inside one should be left open, perhaps for the remainder of the day, so that it has a chance to dry.

Sliding Doors

Sliding doors are treated just as a regular window, except that in many instances there are children’s finger prints or animal nose prints on the lower portion. Use industrial glass cleaner and a razor blade on these areas and make sure that you get down on your knees to see that you’ve gotten off all the greasy marks. Also, on the edge of the sliding screen door, there is often a rubber blade that gets wet as you’re washing the door. If you don’t dry that rubber, and you close it to do the other side, you will drag water over the clean glass and you’ll have to start over.

Trouble Shooting

  • If you’re having problems with streaks after practicing all the techniques, or if you develop a problem after you’ve been at it awhile, there are several things to check.
  • Be sure you are keeping the edge of the squeegee dry, by overlapping each stroke 1-2″ in the dry area. Be sure you are drying the top edge of the window before you start. If the edge of your squeegee gets wet, you’ll streak.
  • How long has it been since you’ve changed the rubber in your squeegee? When the sharp edge starts getting worn down, rounded, knicked, you’ll be working less efficiently. Any nick in the rubber will cause a wet line or streak that is easily identifiable because it will always appear in the same place.
  • If you’re having a problem removing water with the squeegee, check the channel and rubber to see that it’s making contact with the glass across the full length. If not, the channel could be bent. Be careful when handling your squeegee. Don’t drop it, step on it, or bend it in any way. A bent channel needs to be replaced.
  • Sometimes the plastic tips of the strip washer become dislodged, causing the sharp metal ends to poke through the ends of the strip washer sleeve. The exposed metal can scratch glass and wood. Replacement plastic caps are available, if necessary. Immediately replace worn out sleeves.