Removing stubborn limescale marks on exterior windows
Rainwater or sprinkler water has left white drops hard as stone on your windows? Vinegar is no longer enough? Here are the strong solutions.
Recommended Materials
- Hot white vinegar
- Citric acid
- Steel wool 000 (Triple Zero)
- Bathroom anti-limescale product
Steps to follow
Step 1
If cold vinegar doesn't work, try hot vinegar. Heat white vinegar (without boiling it). Soak a cloth or paper towel and 'stick' it on the limescale area. Leave on for 30 min. Heat boosts acidity.
Step 2
The pro mechanical method: 000 steel wool (Triple Zero, very fine, used by cabinetmakers). Rub the DRY window with the dry steel wool. It's impressive but it doesn't scratch the glass (glass is harder than mild steel). It pulverizes the limescale into white dust. Warning, do not use on synthetic glass (plexiglass) or windows with tinted film!
Step 3
The citric acid paste: mix citric acid powder (drugstore section) with a very little water to make a thick paste. Rub the stains with this paste. Citric acid is more powerful than vinegar. Rinse well.
Step 4
As a last resort: toilet or bathroom descaling products (like Viakal or Antikal). Put on gloves, apply to the window, leave on for 5 min (no more, it can attack the glass in the long run), rinse thoroughly.
Frequently Asked Questions
Where does this limescale come from ?
Often from poorly adjusted automatic watering that sprays the windows with hard water, or from rainwater runoff on a concrete or limestone plaster facade just above.
Toothpaste ?
Yes, toothpaste (classic white paste) contains mild abrasives (silica) that can polish light water stains. Rub with a damp cloth.
Precautions
- Always test the steel wool in a corner.
- Protect aluminum or stone frames from acidic products.
