Glass
Chemically tough and mechanically fragile. Almost all damage to glass is grit dragged across it, not the cleaner used on it.
What not to do
Acetic acid (vinegar) may damage Glass
Best avoided
The available guidance advises against this.
The glass paper excludes acids from glass cleaning solutions as a class, naming hydrochloric and hydrofluoric as its examples. Vinegar is not among the acids it names.
Evidence
Supported
Sources
Glass Technical Paper FB01-00: Proper Procedures for Cleaning Architectural Glass Products
National Glass Association (NGA) with the International Window Cleaning Association (IWCA), 2023 · Trade or professional body
Relied on for: That glass cleaning solutions should not include acids, especially muriatic or hydrochloric and hydrofluoric, and that glass can be permanently damaged if improperly cleaned. (states this directly)
Citric acid may damage Glass
Best avoided
The available guidance advises against this.
Evidence
Supported
Sources
Glass Technical Paper FB01-00: Proper Procedures for Cleaning Architectural Glass Products
National Glass Association (NGA) with the International Window Cleaning Association (IWCA), 2023 · Trade or professional body
Relied on for: That glass cleaning solutions should not include acids, and that a small area should be test-cleaned and examined before proceeding. (states this directly)
Precautions
- Test on an inconspicuous area first
In detail
Glass tolerates far more chemistry than most surfaces in a house and far less grit. The glass trade's cleaning paper starts from a mild non-abrasive solution and clean water, and its restrictions are narrow: cleaning solutions should not include acids, hydrochloric and hydrofluoric in particular. Everything else is about mechanics. Bristle brushes and abrasive materials are ruled out, razor blades and metal scrapers are excluded from routine cleaning, and metal contact with the surface is to be avoided. The mechanism it gives for scratching is not the cloth or the cleaner but the particles between them: sufficient water helps prevent abrasive particles being trapped between the glass and the tool, and the cleaner has to be diligent about keeping grit off the glass altogether. Scratches may be invisible under a grey sky and obvious when the sun is low, so a bad method can seem fine for months. Water is the other half: the professional pure-water method requires below 20 parts per million dissolved solids and states tap water is not acceptable, because rinse water evaporates in place.
Properties
Sensitivity
- Acids
- Sensitive
- Alkalis
- Not known
- Chlorine bleach
- Not applicable
- Heat
- Not known
- Abrasion
- Sensitive
- Porous
- Not applicable
“Not known” means nobody has established this, not that the material is unaffected.
What works
Dusting is safe on, in specific conditions, Glass
Safe only in specific conditions
This is only appropriate within specific limits. Outside those limits, no claim is made.
Only within these limits:
- Dry dusting first, with a lint-free cloth that will not scratch
- Vacuum with the nozzle about an inch clear and a soft brush directing dust towards it where the build-up is heavy
- HEPA-filtered machine preferred, suction adjustable and reduced for small or fragile items
Dusting a hard surface is preservation rather than housekeeping here: dust is abrasive, scratches glass and glazed ceramic, and in humid air reacts with atmospheric acids to degrade them.
Evidence
Supported
Sources
Conserve O Gram 8/1: Removing Dust From Ceramic And Glass Objects
National Park Service, US Department of the Interior, 1993 · Government or regulator
Relied on for: That dry wiping is the recommended procedure for regularly-shaped smooth-textured objects, that vacuuming is done with the nozzle about one inch from the surface with a soft brush, that a HEPA-filtered machine with adjustable suction is preferable, and that dust is abrasive and can scratch and degrade glass and glazed ceramics. (states this directly)
Denatured alcohol is safe on, in specific conditions, Glass
Safe only in specific conditions
This is only appropriate within specific limits. Outside those limits, no claim is made.
Only within these limits:
- Ten parts denatured alcohol, eight parts distilled or deionised water, one part NON-DETERGENT household ammonia
- Only where dry dusting has not been enough
- Stable glass only — not where the surface is unstable, cracked, or carries over-glaze decoration
- Turn the cloth to a clean face as it loads with dirt
A specified ratio rather than a splash on a cloth. The ammonia in it can react with unstable glazed and glass surfaces, which is why the stability condition is not boilerplate.
Precautions
- Never mix with other cleaning products
- Ventilate the area
- Test on an inconspicuous area first
Evidence
Supported
Sources
Conserve O Gram 8/1: Removing Dust From Ceramic And Glass Objects
National Park Service, US Department of the Interior, 1993 · Government or regulator
Relied on for: That damp wiping may be done on stable glass and high-fired ceramic objects without cracks in the glaze or over-glaze decoration, using a solution of ten parts denatured alcohol, eight parts distilled or deionised water and one part non-detergent household ammonia. (states this directly)
Ammonia is safe on, in specific conditions, Glass
Safe only in specific conditions
This is only appropriate within specific limits. Outside those limits, no claim is made.
Only within these limits:
- One part NON-DETERGENT household ammonia to ten parts denatured alcohol and eight parts distilled or deionised water
- Never with any chlorine product
- Stable, uncracked, undecorated surfaces only
The source's own caution is chemical rather than procedural: ammonia can react with unstable glazed and glass surfaces, and where stability is in doubt the instruction is to ask rather than to try.
Precautions
- Never mix with other cleaning products
- Ventilate the area
Evidence
Supported
Sources
Conserve O Gram 8/1: Removing Dust From Ceramic And Glass Objects
National Park Service, US Department of the Interior, 1993 · Government or regulator
Relied on for: That the damp-wipe solution contains one part non-detergent household ammonia, and that ammonia can react chemically with unstable glazed and glass surfaces. (states this directly)
Detergent is safe on, in specific conditions, Glass
Safe only in specific conditions
This is only appropriate within specific limits. Outside those limits, no claim is made.
Only within these limits:
- Structurally sound surfaces only
- Hot water with household detergent and a stiff brush; the aim is physical removal, not killing
- Dry completely within 24 to 48 hours
- Correct the moisture problem first
Named by a state health department among the materials that can be cleaned rather than discarded when mouldy: hard plastic, solid wood, concrete, metal and glass.
Precautions
- Ventilate the area
- Wear gloves
Evidence
Supported
Sources
Minnesota Department of Health · Government or regulator
Relied on for: That glass among other hard materials can be cleaned if structurally sound, using a stiff brush with hot water and household detergent to remove the physical mould growth. (states this directly)
United States Environmental Protection Agency (EPA) · Government or regulator
Relied on for: That mould is scrubbed off hard surfaces with detergent and water and dried completely. (states this directly)
Why
- Glass is explained by Leaching and clouded glass
Related
- Glass is commonly affected by Label residue
- Glass is commonly affected by Pollen
Hacks and claims involving this
- Vinegar for mirrors and glass Does not work
- Scraping glass clean with a razor blade Does not work
- Cloudy dishwasher glasses can be cleaned Disputed
- Nail polish remover to lift a stubborn mark Supported
When the obvious answer is wrong
How do I get limescale off a shower screen without damaging the glass?
The glass association's cleaning paper excludes acids from glass cleaning solutions as a class, naming hydrochloric and hydrofluoric as its examples, and warns that glass can be permanently damaged if it is infrequently or improperly cleaned. It also rules out the two things people escalate to when the acid does not work: abrasive cleaning materials, and razor blades or metal scrapers, which are excluded from routine cleaning altogether. The mechanism it gives for scratching is not the cleaner but trapped grit, so scrubbing a gritty screen is worse than leaving it.
It cannot be removed safely — prevent it instead: Treat this as a drying problem rather than a cleaning one, because that is where the deposit is actually created. The glass paper is precise about the mechanism from the other direction: its pure-water method requires water below 20 ppm total dissolved solids and states that tap water is not acceptable, because the rinse water is allowed to evaporate in place. Ordinary tap water left to evaporate on a screen deposits exactly what it was carrying. So the intervention with evidence behind it is removing the water before it dries — squeegee or blot the screen after each use, which is the same instruction the sanitaryware manufacturer gives for metal, where allowing water to evaporate forms deposits and the technique is to blot with a dabbing action rather than rub. For scale already established, no supportable method exists on this substrate: the acid that would dissolve it is excluded by the glass authority, and abrasives and blades are excluded too.
Sources for this page
Sources
Glass Technical Paper FB01-00: Proper Procedures for Cleaning Architectural Glass Products
National Glass Association (NGA) with the International Window Cleaning Association (IWCA), 2023 · Trade or professional body
Relied on for: That cleaning uses clean water and a mild non-abrasive solution, that solutions should not include acids especially hydrochloric and hydrofluoric, that razor blades and metal scrapers are excluded from routine cleaning, and that pure-water cleaning requires below 20 ppm dissolved solids because tap water is not acceptable. (states this directly)