How do I clean my leaded glass windows?

Leaded glass doesn't need special treatment. Most of the time, a soft cloth and warm water is genuinely all it takes. The issues I see come from people using products that work fine on modern windows but are harmful to lead and putty over time.

What actually works

Soft, lint-free cloth, warm water. If the glass needs more than that, a small amount of mild dish soap diluted in water is fine. Wipe gently, work in sections, dry as you go. That's it. I know it sounds underwhelming but that's genuinely all most windows need.

What to stay away from

• Vinegar or acidic cleaners they attack the lead surface and speed up oxidation
• Ammonia-based cleaners like Windex bad for the lead and putty over time
• Anything abrasive you'll scratch the glass and gouge the lead
• Pressure washing or soaking water forced into the lead channels softens the putty that holds everything in place
• Steam cleaners the heat loosens the putty seal

What about the lead lines themselves?

You can wipe over them gently. Don't scrub. Over time, lead develops a patina a slightly darkened matte surface that's completely normal. Aggressive cleaning strips that patina and leaves the lead looking inconsistent and raw. It's not a look you want.

When it's beyond a wipe-down

If your lead lines have heavy white or grey powder buildup, or the glass has deep oxidation staining that a cloth won't touch, that's worth a professional look. I do on-site cleaning for homeowners across Toronto who want a proper deep clean without the risk of damaging the window themselves.