Glass Restoration Guide

Why Does Glass Need Restoration?

Glass is not perfectly smooth; If it was, It would be easy to remove most forms of dirt. It is pitted with microscopic indents which allow solids to bond to the surface. When glass is cleaned regularly, these solids are removed before they can cause any permanent damage to the glass. When neglected, then the glass will start to corrode and become damaged.

The best opportunity to restore a piece of glass or window is when the corrosion is first noticed.  The corrosion can be removed and the glass can be reprotected against further damage. If a window is too badly damaged, a contractor would suggest the window must be replaced. Window and glass replacement is very costly! That is where glass restoration comes into play and that's where you come in to help.

Customers that are faced with a potentially expensive window replacement will be looking for alternatives to save them money. Glass restoration can be used to significantly prolong the life of most windows by impeding the progression of corrosion and removing a majority of staining on the surface.

If you're just getting into Glass Restoration, The WCR Nation Podcast has a an episode on it!

What Causes Glass Corrosion?

Glass is constantly going through wear and tear. Whether it's outside elements like air pollution, acid rain, dust and airborne grit, and hard water deposits, or more localized elements such as corrosive cleaning materials, all of these elements slowly deteriorate window glass. With all of these elements, they can haze, erode, etch, and pit glass on thousands of windows daily! It doesn't matter what causes it, the result is always the same.

  • Glass Oxidation

    Glass oxidation is when a window’s glass appears “hazy” and has a while “Etched” look, this typically occurs on the outside part of a window, but can occur on the inside or even between the panes. 

    This is caused by metal around the exterior window that has been exposed to rain or humid conditions causing the metal to slowly deteriorate and become “oxidized”. Most commonly seen on windows with metal frames or screens, this condition penetrates glass and renders regular window cleaning techniques ineffective.

  • Hard Water Stains

    Hard water staining is when a window’s glass appears to be etched with white “teardrop” shaped deposits. Often times it can also look as though a liquid substance has been “dripped” down the window’s surface, therefore causing a stain. 

    Hard water stains occur when rain travels over the exterior building surface i.e (concrete, paint, and stain), and deposits minerals from these surfaces onto the window below. Further causes of hard water stains include acid rain, salt spray, sprinkler systems, and rust. All of these cause water stains because they carry and deposit harmful minerals to the glass’s surface area.

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What is Hard Water?

Hard water contains dissolved calcium and magnesium ions. Common referred to as “hardness minerals” dissolved calcium and magnesium can cause numerous problems when present in the water supply.

As the water falls from the sky in its various forms, it absorbs carbon dioxide in the air and becomes slightly acidic. Water in this weak acid state reaches and enters the ground. Since it’s acidic, it absorbs calcium from the layers of rock through which it passes.

The minerals neutralize the water’s acidity but also make it hard. Then the water finds its way into larger bodies of water both above and below ground, and eventually into our homes. 

Water hardness is typically measured in “parts per million,” an indication o the quantity of dissolved calcium and magnesium the water contains. In amounts as small as one part per million, water is classified as “hard” to a certain degree. Most homes use water that is considerably harder.

If you're looking to specifically target hard water stains, we have an additional guide on Hard Water Stain Removal.

In this video, Dan Fields** discusses HardWater Spot Removal. He displays the differences between certain hard water spots and also covers tin etch haze and glass corrosion. Learn more about the use of chemicals like hydrofluoric and phosphoric acids for the removal of hard water spots. He also dives into the problems associated with acid use.

**All video footage belongs to Dan Fields. We thank him for educating the industry on the importance of this issue.

Materials and Equipment

The materials and equipment for glass restoration are very basic. Odds are that as a window cleaner you probably already have almost all of the equipment you will need.



    There are many different styles and brands of squeegees available on the market and for the purpose of glass restoration, practically any squeegee will do.  

    Strip Washers

    For optimal results, you will need at least 2 different strip washers for glass restoration. One to clean the windows and then a separate strip washer to apply the restoration chemical to the glass. The strip washer you use to apply the chemical needs to have a softly, mildly abrasive sleeve to gently apply the chemical to the glass.


    These are lint-free blue towels that are also called surgical towels. These are ultra-absorbent towels that you will use to wipe the edges of the window and catch any drips that run down the glass. They do not smear or streak windows as white towels do. 

    Window Cleaning Solution

    This is your standard window cleaning solution that you use regularly to clean windows. In order for glass restoration to work, the glass must first be cleaned before you can restore it.

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    Crystal Clear 550

    CC550 is a heavy-duty glass cleaning agent for the removal of hard water deposits, alkali residues, haze, and other atmospheric pollutants. Crystal Clear 550 will dissolve away mineral deposits from the surface of the glass and help prevent re-deposit. CC550 can be purchased in either pint bottles, gallon jugs, 5-gallon buckets, or 55-gallon drums. 


    CC550 is a highly acidic compound. One of its main ingredients is hydrofluoric acid, which works wonders on glass, but is not very friendly to your skin or body. For this reason, you must always wear chemical-resistant gloves when working with any chmical. These are NOT the same as the yellow gloves you use in the kitchen, the gloves you need are designed to withstand contact with acids.


    You will also need to wear protective eyewear when working with CC550 to protect your eyes from splashes and vapors. Make sure that the protective goggles you buy have splash-proof vents to prevent any leakage into the goggles. 


    A respirator is not absolutely necessary, although some insurance carriers do require it. Using a respirator when dealing with any type of chemical is always a good idea. CC550 is not particularly dangerous, but it’s always better to be safe than sorry. 

Stages Of Glass Corrosion

There are 3 main stages of glass corrosion, each stage identifies a different type and severity of corrosion and the more severe the corrosion the less effective your restoration methods will be.

Stage 1 Corrosion - This is the most basic level of glass corrosion and is defined as glass with light corrosion, hazing, or slight discoloration, with little or no damage to the glass. With Stage 1 corrosion, you can run your fingers across the glass and it should be still smooth and slippery. Glass with stage 1 corrosion can typically be restored to 95% clarity.

Stage 2 Corrosion -  Occurs when the mineral deposits are no longer on the surface of the glass. The deposits have started to break down the molecular structure of the glass, leaving an etched or thick white haze on the glass. Glass with stage 2 corrosion will be rough and dry to the touch. Glass with stage 2 corrosion can typically be restored to 80%-85% clarity. 

Stage 3 Corrosion -  This is the final stage of corrosion and at this point, the chemical and mineral deposits have completely compromised the integrity of the glass and have caused it to fail. Glass with stage 3 corrosion can not be restored at all and will only further weaken and damage the glass. Glass in this condition must be replaced.

Glass Restoration Method

The entire process of glass restoration should take no more than a few minutes per window. This means big money for you as you will be able to solve a customer’s problem on the spot and charge a premium for your service. 

Clean The Window

Restorative chemicals are not glass cleaner, it will not remove regular dirt, grime, oils, and other debris from the glass. Therefore, the first step in restoring glass is to clean the window using your normal window cleaning methods. The idea is to get the window in as pristine of a condition as possible before you apply the chemical.

Protective Gear

When using any chemical, it is very important to follow safe handling procedures so that you remain safe while using it. After you have cleaned the window you need to put on your goggles, respirator mask, and rubber gloves before handling the chemical. 

Apply Chemical To Strip Washer

Once you have your protective gear on, it’s time to apply a small amount of CC550 or your preferred restorative chemical to the strip washer you have set aside just for glass restoration. A  little goes a long way, and all you really need to do is moisten one tip and the length of one side of the strip washer.

Apply Chemical To Window

Now that your strip washer is coated, you can now apply it to the glass.  Get even coverage over the entire surface of the glass while paying attention to the corners and edges of the glass as well. There is no need to press hard and the best technique uses tight circular scrubbing motions to work the chemical into the glass. 

Let Chemical Sit On Glass

Once you have coated the entire window with a restorative chemical, you should now step back and let it sit on the glass for about 30 seconds. For stubborn stains, you can leave it on the glass for a bit longer if needed. After 30 seconds, use your strip washer to gently scrub the window again to agitate the mineral deposits and cause them to dissolve. 

Wash Off Glass

After letting the chemical sit on the glass and doing your final scrubbing, you are now ready to rinse off the window. There are two main methods for doing this. The first is to use your regular strip washer and your standard cleaning solution to scrub off the chemical. And the other method is to use a water hose to flush the chemical off the glass. After cleaning the chemical of the glass, use a squeegee to do a quick clean of the window to see if all the staining has been removed.

Re-Clean and Touch Up Window

Once the stain has been removed all the way or as good as it’s going to get, it’s now time to re-clean the window one final time using your regular cleaning methods to finish the window out and show off your glass restoration work.