Most marks on glass are deposits sitting on the surface and will come off with the right approach. Etching is different: the glass itself has been damaged, and no product will remove it.
Stain or etching? Test before you spend money
The fingernail test
Run a fingernail lightly across the mark. If you can feel a raised edge, it is a deposit and it will come off. If the glass feels perfectly smooth but you can still see the mark, the glass is etched and no amount of cleaning will change it.
What each stain needs
| Mark | What it is | Approach |
|---|---|---|
| White spotting from sprinklers | Mineral deposits from hard water | Mild acidic cleaner, dwell time, gentle agitation, rinse |
| Paint spots | Dried paint sitting on the surface | Soften with warm soapy water, then a plastic scraper at a low angle |
| Tree sap | Resin, which softens with solvent | Isopropyl alcohol on a cloth, hold to soften, then wipe |
| Sticker and tape residue | Adhesive | Warm soapy water to soften, then alcohol; never a dry scrape |
| Silicone smears | Cured sealant | Very difficult; a plastic scraper and patience, and it may not fully clear |
| Rust marks | Iron in water, or a nearby metal fixing | Acidic cleaner; fix the source or it comes back |
| Concrete or render splash | Alkaline and it etches quickly | Remove immediately; once it has etched, it is permanent |
| Cloudy haze that will not shift | Etching, or degraded film | Cannot be cleaned; glass or film replacement |
Scraping, if you must
A blade will remove paint and hardened deposits, and it will also scratch glass permanently if used badly. If it is being used at all:
- Wet the glass first, always — never scrape dry
- Hold the blade at a low angle, around 30 degrees
- Push in one direction only; never drag it back across
- Use a fresh blade — a nicked one is what scratches
- Never on tinted, frosted or coated glass
- Never on toughened glass with a visible surface coating
If you are not confident, do not. A scratched pane is a replacement, not a clean.
Hard water spotting is the common one
Water dries on the glass and leaves the minerals behind. Left long enough, those minerals bond and eventually etch. Early spotting comes off easily; years of it may not come off at all.
Prevention beats removal
- Redirect sprinklers so they do not hit glass
- Dry shower screens after use rather than letting water evaporate on them
- Consider a screen treatment so water beads off
- Cover glass before painting or rendering nearby
- Deal with new marks quickly — almost everything comes off when fresh
We do window and gutter cleaning across Melbourne's eastern suburbs — glass, frames, sills, tracks and flyscreens. Ask us for a quote and we will tell you honestly what can be reached safely at your place.
Frequently asked questions
Can etched glass be repaired?
Light etching can sometimes be polished by a glass specialist, but it is skilled work and often costs more than replacement. It is not a cleaning job.
What removes paint from glass?
Soften with warm soapy water, then a fresh blade at a low angle on wet glass, pushing in one direction. Never on tinted, frosted or coated glass.
Will vinegar remove hard water spots?
On fresh spotting, often yes. On deposits that have bonded over years, it will not, and no household product will.
3 Piglets Cleaning
We are a Croydon-based cleaning company serving Melbourne's eastern and south-eastern suburbs. Our technicians are police-checked and fully insured, and those working with NDIS participants and older clients hold NDIS Worker Screening Clearances. More about us.
