Cloudy dishwasher glasses can be cleaned

Does it work?

Disputed

Disputed. Publishing it as simply true would send people after permanent damage with a bottle of vinegar; publishing it as false would deny a treatment that works on the commoner condition.

This is a verdict on whether the technique is effective. Whether it is safe on a particular surface is a separate question, answered below.

Why it works

Where the cloudiness is hard water scale, an acid dissolves the carbonate and the glass clears — which is why vinegar and citric acid work often enough to keep the claim alive. Where it is etching, the glass surface has itself been attacked under soft water and excess detergent, so there is no deposit for an acid to act on and the appearance is the damaged surface.

Background

Glasses come out of the dishwasher cloudy and the internet has a dozen fixes. The manufacturer separates two conditions that look the same and are not. A white FILM is hard water mineral deposit: it is a deposit, it sits on the glass, and it comes off — the guide treats interior film with dishwasher detergent on a damp sponge, and general film with an empty cycle and white vinegar, or citric acid crystals if vinegar fails. CLOUDINESS is different. The guide identifies it as etching, states plainly that it is PERMANENT, and attributes it to a combination of soft water and too much detergent. Nothing removes it because nothing is on the glass; the surface itself has been attacked. The practical value is in the test rather than the treatment: if a vinegar or citric acid cycle clears it, it was deposit, and if nothing shifts it, it is etching and no product will. The prevention the guide gives is specific and free — use less detergent if the water is soft, and wash glassware on the shortest cycle that gets it clean. Water entering above 150°F is named as a contributing factor.

What it does not do

• One manufacturer's guidance for two named models
• The guide gives no way to tell etching from film by eye, only by whether treatment works
• It does not quantify how much detergent is too much for a given water hardness

What to use instead

• Descaling — Dissolving mineral deposits with an acid. Effective, well understood, and the wrong answer on any surface made of the same mineral.
• Citric acid — A mild solid acid, widely used for descaling. Effective on limescale, and destructive to carbonate stone for exactly the same reason.
• Acetic acid (vinegar) — The acid in vinegar. Genuinely effective on limescale and mineral films, and routinely recommended for surfaces it should never touch.