How To: Clean Hazy Glass

By Scott Sidler April 9, 2018

how to clean hazy glassHow do you clean hazy glass? If you’ve got an old house I’m sure you’ve asked this question before. It’s amazing how nice clean, sparkly glass looks. After staring through grimy windows for years, when that old wavy glass is brought back to its original shine it totally transforms your window’s appearance and the feel of a room.

You might think a simple glass cleaner is the key- and while those can help, there are better ways to get a more beautiful shine with simple products like I’ll discuss below.

Don’t miss the quick video below showing you the techniques and results of cleaning. You can use these techniques both in place and if you have your glass out during the window restoration process. Be sure to subscribe to my YouTube channel for more videos like this on a regular basis by clicking here.

Clean Hazy Glass in Place

Most folks need to clean their glass in place rather than having it out on the table like you do during window or door restoration, but the process is the same, except that its a little harder to reach. As long as you can safely access the outside of the window, then you can do this full “de-hazing” process. If you don’t have good access to the window, then a simple washing is really all you can expect unless you plan to pull the sash out to restore your windows.

Step 1 Rinse with Soap & Water

Rinse the glass with simple dish soap and water first. You can really drench it rather than just a light misting. This will start softening the built up grime and dirt.

Step 2 Razor Blade the Glass

Grab a flat razor blade or better yet a glass razor scraper and scrape across the surface of the glass. This will remove dirt, grime, paint over spray and a majority of the gross build up. Be careful not to gouge the putty or dig into and parts of the wood.

Step 3 Wipe Clean

Rinse with some clean water and wipe the glass clean and dry it with a clean rag to gather any of the left overs. If the glass looks fine, you can stop here, but if you still have a hazy appearance, then move onto step 4 below.

Step 4 Polish Glass

To get rid of stubborn haziness and built up mineral deposits, you need a glass polishing compound like CRL Sparkle which you can find in my store. We polish all of our glass because it really gives it a shine. Think of it kind of like getting your car’s headlights polished. It lightly abrades the surface polishing off imperfections and haze.

With a clean rag, apply the polish in a circular motion much like waxing a car. Really work it in hard and rub the surface good to remove the build up. Let it air dry until it develops a hazy, white appearance and then buff it off with a new clean rag. Once you have all the residue off, you should be left with a shiny new piece of glass!

Clean Hazy Glass in the Shop

If you happen to have the glass out of your sash during the restoration process, then that just makes the job so much easier. I prefer to find a tub of some sort to let the glass soak in the water and dish soap mixture for as long as you can. This really softens up the leftover glazing putty or paint and makes the cleaning process that much easier.

From there, the process is exactly the same as above. Be careful not to use some of the chemical glass cleaners because I have seen them cause issues with paint adhesion later when you go to glaze and paint your window. Ammonia is not a friend of new paint, so steer clear and stick with simple soap and water.

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4 thoughts on “How To: Clean Hazy Glass”

  1. I have tried sop & water, vinegsr, razor blades etc. I have hazy streaks which I think are due to bi monthly pesticide spraying. Any suggestions on how to eliminate them?

  2. 0000 steel wool and a can of elbow grease work pretty dang good and doesn’t scratch the glass. Just have a plan for the steel wool dust it leaves. Compressed air or your favorite vacuum attachment work.

    1. I’d stay away from steel wool. I have a few panes that have dull areas around the edges from that. Maybe some glass is softer? Razor blades, soap and water.

  3. I think you have previously mentioned films for glass, primarily in the context of insulation, where you can get coatings that can either let light in and trap the heat inside, or block the heat outside while letting visible light in. (Do you have any favorite products along these lines?)
    If one is doing window restoration, is it a good thing (i.e., easier overall) to put the films on before the glass goes back into the frame, or to wait until the window has been fully restored, and put the film on as the last step, or is it 6 of one and half a dozen of the other?
    Thanks, as always

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