Mirrored glass
Glass with a reflective backing and exposed edges. The trade body's guidance rules out both vinegar and ammonia — which is nearly everything sold for cleaning it.
What not to do
Acetic acid (vinegar) is unsafe on Mirrored glass
Unsafe
Do not do this. The risk is established, and it is described below.
The single most common domestic glass remedy, named by the trade body as one not to use.
Precautions
- Test on an inconspicuous area first
- Limit the contact time
Evidence
Strongly supported
Sources
Glass Technical Paper FB06-05: Proper Procedures for Cleaning Flat Glass Mirrors
National Glass Association (NGA), Mirror Division, 2019 · Trade or professional body
Relied on for: That commercial mirror cleaners containing ammonia or vinegar must not be used, and that acid or alkali cleaners can attack the front surface, the edges and the backing. (states this directly)
Ammonia is unsafe on Mirrored glass
Unsafe
Do not do this. The risk is established, and it is described below.
Precautions
- Test on an inconspicuous area first
- Ventilate the area
- Never mix with other cleaning products
Evidence
Strongly supported
Sources
Glass Technical Paper FB06-05: Proper Procedures for Cleaning Flat Glass Mirrors
National Glass Association (NGA), Mirror Division, 2019 · Trade or professional body
Relied on for: That commercial mirror cleaners containing ammonia must not be used, and that alkali cleaners can attack the front surface, the edges and the backing. (states this directly)
Citric acid is unsafe on Mirrored glass
Unsafe
Do not do this. The risk is established, and it is described below.
The mirror paper prohibits acid cleaners as a class rather than naming each acid, so this follows the class statement.
Precautions
- Test on an inconspicuous area first
- Limit the contact time
Evidence
Supported
Sources
Glass Technical Paper FB06-05: Proper Procedures for Cleaning Flat Glass Mirrors
National Glass Association (NGA), Mirror Division, 2019 · Trade or professional body
Relied on for: That acid or alkali cleaners must not be used on mirrors because either can attack the front surface, the edges and the backing. (states this directly)
Scouring powder is unsafe on Mirrored glass
Unsafe
Do not do this. The risk is established, and it is described below.
Evidence
Strongly supported
Sources
Glass Technical Paper FB06-05: Proper Procedures for Cleaning Flat Glass Mirrors
National Glass Association (NGA), Mirror Division, 2019 · Trade or professional body
Relied on for: That abrasive materials are excluded from mirrors, which carry a reflective coating and an exposed backing. (states this directly)
Precautions
- Test on an inconspicuous area first
- Limit the contact time
In detail
A mirror is not a piece of glass, it is a piece of glass with a metallic coating and a protective backing, and every serious risk is at the edges where those layers are exposed. The glass trade body's care paper is organised around that: getting the edges wet can produce the failure known as black edge, and edges that do get wet should be dried at once. Its first recommendation is that the best and safest cleaner for a mirror is clean warm water on a wrung-out lint-free cloth, dried immediately. Its most surprising one is a prohibition: do not use commercial mirror cleaners containing ammonia OR vinegar, and do not use acid or alkali cleaners, because either can attack the front surface, the edges and the backing. Between them that rules out most of what is sold or recommended for mirrors, including the household remedy people are most confident about. Cleaner is applied to the cloth and never sprayed at the mirror, specifically so it cannot run into the edges. For stubborn marks the paper recommends 0000 oil-free steel wool and explicitly not solvents, which attack the edges and backing.
Properties
Sensitivity
- Acids
- Sensitive
- Alkalis
- Sensitive
- Chlorine bleach
- Not known
- Heat
- Not known
- Abrasion
- Sensitive
- Porous
- Not applicable
“Not known” means nobody has established this, not that the material is unaffected.
What works
Water is safe on, in specific conditions, Mirrored glass
Safe only in specific conditions
This is only appropriate within specific limits. Outside those limits, no claim is made.
Only within these limits:
- Clean WARM water on a soft lint-free cloth, wrung out
- Dry the mirror immediately
- Keep liquid off the edges — wet edges cause the damage known as black edge, and any that do get wet are dried immediately
- Never spray onto the mirror; apply to the cloth, specifically so it cannot reach the edges
The trade body calls plain warm water the very best and safest cleaner for a mirror, and prohibits the commercial mirror cleaners containing ammonia or vinegar that most people reach for.
Precautions
- Rinse thoroughly afterwards
Evidence
Supported
Sources
Glass Technical Paper FB06-05: Proper Procedures for Cleaning Flat Glass Mirrors
National Glass Association (NGA), Mirror Division, 2019 · Trade or professional body
Relied on for: That the very best and safest cleaner for a mirror is clean warm water on a soft lint-free cloth wrung out with the mirror dried immediately, that cleaner must not be sprayed directly onto the mirror, and that wet edges cause black edge damage. (states this directly)
Steel wool is safe on, in specific conditions, Mirrored glass
Safe only in specific conditions
This is only appropriate within specific limits. Outside those limits, no claim is made.
Only within these limits:
- 0000 grade, OIL-FREE, for stubborn marks only
- Specifically NOT solvents, which attack the edges and the backing
- Finish by making sure all joints and edges are dry
A rare case where the abrasive is the safe option and the solvent is not. The vulnerable part of a mirror is its backing, and a solvent reaches it where an oil-free wool does not.
Precautions
- Test on an inconspicuous area first
Evidence
Supported
Sources
Glass Technical Paper FB06-05: Proper Procedures for Cleaning Flat Glass Mirrors
National Glass Association (NGA), Mirror Division, 2019 · Trade or professional body
Relied on for: That for stubborn marks the recommendation is 0000 oil-free steel wool and specifically not solvents, because solvents attack the edges and backing. (states this directly)
Why
- Mirrored glass is explained by Coating thickness
Hacks and claims involving this
- Vinegar for mirrors and glass Does not work
- Never use an abrasive in the bathroom Disputed
When the obvious answer is wrong
How do I get hard water spots off a bathroom mirror without wrecking it?
A mirror is not a pane of glass. It is glass with a reflective coating and a protective backing, and both are exposed at every edge. The glass industry's mirror division states that acid or alkali cleaners can attack the front surface, the edges and the backing, and names cleaners containing ammonia or vinegar specifically as ones not to use. The failure is called black edge, it starts where liquid runs into the perimeter, and it is degradation of the mirror rather than dirt on it.
A different kind of treatment works: Change the mechanism from dissolving to drying. The mirror division's own recommendation is clean warm water on a soft lint-free cloth, wrung out, with the mirror dried immediately afterwards — which works because the deposit is created at the moment of evaporation rather than while the water sits. Apply any liquid to the cloth and never spray it at the mirror, so nothing can run down into the edges, and finish by checking that the joints and edges are dry. Where a mark will not come off with water, the paper's stated method is 0000 oil-free steel wool, explicitly not a solvent, since solvents attack the edges and backing too. The prevention is the whole answer in a bathroom: ventilate, and wipe the mirror dry rather than letting the condensation evaporate on it.
Sources for this page
Sources
Glass Technical Paper FB06-05: Proper Procedures for Cleaning Flat Glass Mirrors
National Glass Association (NGA), Mirror Division, 2019 · Trade or professional body
Relied on for: That wetting mirror edges causes black edge, that clean warm water on a wrung lint-free cloth is the safest cleaner, that cleaners containing ammonia or vinegar and acid or alkali cleaners must not be used because they attack the surface, edges and backing, that cleaner is applied to the cloth rather than sprayed, and that 0000 oil-free steel wool rather than solvent is used for stubborn marks. (states this directly)