Spring in Hamilton means a winter of road salt, brake dust off the Linc and escarpment grit baked onto the glass. It comes off easily. The trouble starts when people reach for something sharp.
The routine that works
- Brush or vacuum the dry grit off first. Every scratch we see started as sand dragged across dry glass.
- Rinse with plain water. Hose pressure, not pressure washer pressure.
- Wash with warm water and a drop of dish soap using a microfibre cloth or a soft sponge.
- Squeegee top to bottom, wiping the blade each pass.
- Dry the edges and the sill with a cloth so water is not sitting against the frame.
Do it on a cloudy day or in the shade. In direct sun the water dries before you can pull it off and you get the streaks you were trying to avoid.
What damages glass and seals
- Razor blades and scrapers. They leave fine parallel lines you notice for the rest of the window's life. On coated glass they take the coating with them.
- Scouring pads, steel wool, magic erasers. Abrasive by design.
- Pressure washers at the perimeter. Forcing water into the seal of a double glazed unit is one of the fastest ways to make it fog. Keep the wand well back and never aim it at the edge or the caulking.
- Ammonia and strong solvents on a sealed unit. They attack the perimeter sealant and the gaskets.
- Vinegar on stone sills and aluminum. Fine on glass, hard on some surrounding materials.
Low-E, and which side it is on
Low-E is a microscopically thin metallic coating that reflects heat. On almost every sealed unit sold in Ontario it sits on a surface facing into the sealed cavity, where you cannot touch it. That is why normal cleaning does not hurt it.
Where you can damage a coating is on applied film or a storm pane with a surface coating. If the glass has a faint bronze or blue cast at an angle, treat it gently: soap, water, soft cloth, nothing else.
Stains that are not dirt
Some marks do not wash off, and knowing which is which saves you scrubbing.
| Mark | What it is | Fix |
|---|---|---|
| Milky haze between panes | Failed seal, moisture inside | New sealed unit, $350 to $650 |
| White cloudy patches that never move | Mineral etching from sprinkler water | Permanent, replace if it bothers you |
| Rainbow film from the bottom corners | Residue inside a failed unit | New sealed unit |
| Fine parallel lines | Scratches from a scraper | Permanent |
| Wipes off inside | Indoor humidity | Ventilate, run fans |
If it will not wipe off either surface, it is inside the unit and no cleaner will reach it.
While you are there
Look at the caulking and the weep holes. Cracked caulking lets water sit at the edge of the pane, which is where seals fail and cold-morning cracks start. Caulking is $75 to $150 per window and is the cheapest thing you can do for the life of your glass. Blocked weep holes at the bottom of the frame just need a poke with a wire.
Spot fog, a crack or a chip while cleaning? Send us a photo and the size of the glass and we will give you a price on the call.