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I love historic wavy glass!  It’s one of those irreplaceable features that gives old windows their soul. If you’re restoring original windows, keeping the original glass—and making it sparkle again—is worth the effort. In this post (and the video below), Melanie from Glaze Craft Windows in Virginia walks us through how to safely clean and preserve historic glass using budget-friendly tools and gentle techniques.

Step 1: Start with the Right Cleaning Solution

Forget harsh chemicals. Melanie recommends a simple, affordable mix: 1 part vinegar to 15 parts water, using the strongest vinegar you can find. It’s gentle on old glass but tough enough to cut through grime, soot, and buildup from decades past.

Spray it on lightly or apply with a soft cloth. For stubborn spots, give it time to soak in.

Tip: White cleaning vinegar (6–10% acidity) works better than standard kitchen vinegar.

Step 2: Protect the Glass While You Work

Before you do anything else, lay towels down on your work surface or sash. Historic glass—especially thinner panes or wavy varieties—is easy to crack under pressure. Don’t risk it. Padding helps absorb impact if the glass shifts or tools slip.

Step 3:  Wet the Glass and Scrape with a Razor Blade

Simply spray the glass down with lots of cleaning solution, and then use flat razor blades to carefully scrape off the old paint.  The cleaning solution helps prevent any scratching.  Please make sure you have a cleaning solution on the glass when you’re scraping it, and don’t scrape it dry, or you risk scratching the glass.

Step 4: Finish with Triple-Zero Steel Wool

Once most of the paint and residue is gone, it’s time to polish. Melanie uses 000 (triple-zero) steel wool for the final pass. Use it only after spraying with your vinegar solution—never dry.

This step safely removes lingering paint specks and haze without scratching the glass.

Additional Note: Final Cleaning after Glazing

Not covered in this video is Melanie’s method for cleaning the glass once it’s back in the sash and has been glazed. For that final cleaning step, she likes to mix a few drops of dish soap with a generous splash of ethanol (denatured alcohol) into a spray bottle full of water. She then cleans the glass using this solution. This method picks up any oils left over from the putty during the glazing process.

Final Thoughts

Preserving wavy glass isn’t just about looks—it’s about saving history. With the right care, this beautiful  panes can last another hundred years. No fancy products, no big budget. Just vinegar, patience, and a little bit of steel wool!

Watch the full video to see these steps in action, and check out the other posts on LowBudgetWindowRestoration.com for more tips on keeping your windows beautiful and intact.