Neighbours talk. A tiny, old-school fix turns heads.
In Amiens, a pair have turned a humble potato into a kitchen sidekick that keeps their windows clear through the daily dinner rush. Word has travelled, because the method costs pennies, takes minutes and relies on simple physics rather than pricey sprays.
A fog-free window that people can actually see through
Morning coffee, evening soups, boiling pasta. Warm, moist air hits a cold pane and fog forms. Most of us grab a cloth, smear the mist, and repeat. This couple went another way. They rub a cut potato over clean glass, then buff it. The thin film left behind changes how water behaves on the surface.
The trick creates a hydrophilic skin. Instead of forming tight beads that block light, water spreads into a thin, see-through sheet.
That means fewer finger marks, fewer drips on window sills, and a view that actually survives a rolling boil. It is low-tech, quick and oddly satisfying. And yes, it works in winter when condensation bites hardest.
How the 3-minute method works
Grab one raw potato. Make sure the glass is clean and completely dry. Then follow this routine.
- Cut the potato in half and lightly blot the cut face if it looks very wet.
- Rub the cut face over the pane in broad circles, covering the entire surface without pressing hard.
- Wait about a minute for a faint, matte haze to settle.
- Buff with a dry microfibre cloth until the glass looks clear and bright.
- Repeat every 2–3 weeks in colder months, or monthly in mild weather.
Keep it simple: potato, pause, polish. Then crack a window or run the extractor for five minutes after a heavy boil.
Why it works: the physics in plain words
Condensation happens when warm, water-laden air cools suddenly on contact with a cold surface. If the glass encourages water to bead, you get a milky veil. Change the surface energy and water flattens. The result is a clearer view because light scatters less through a film than through millions of micro-droplets.
Potato starch is the quiet star here. A whisper-thin layer alters the contact angle between water and glass. That layer is invisible once buffed correctly. It is also easy to renew and remove with a standard clean.
What about modern double glazing?
The method is for the room-facing side of the pane. It does not touch cavity seals. Avoid scrubbing along the perimeter gaskets. Do not apply to specialist coatings marked “self-cleaning”, “tinted” or “anti-glare” without checking the manufacturer’s guidance.
Does it beat pricier options in real kitchens?
| Method | Time to apply | Approximate cost | Typical longevity | Notes |
|---|---|---|---|---|
| Cut potato + buff | 3 minutes per pane | £0.05 per use | 2–3 weeks | Natural starch film; needs proper buffing |
| Washing-up liquid (diluted) | 3 minutes | Pennies | 1–2 weeks | Apply thinly, buff to a shine |
| Shaving foam (pea-sized) | 4 minutes | £0.10 per use | 2–3 weeks | Can streak if overdone |
| Commercial anti-fog spray | 2 minutes | £8–£15 per bottle | 1–4 weeks | Fast, but cost adds up |
| Do nothing | — | — | — | Repeated wiping, more smears, damp sills |
Real numbers you can use at home
Most households wipe kitchen windows for 5–10 minutes per week in winter. If a 3-minute treatment gives you two to three fog-light weeks, you bank roughly 120 minutes across a month. That is two hours you can spend cooking, eating or not thinking about streaks. The cost is negligible. A single potato treats several panes and still goes into the soup.
There is a small side benefit: less aggressive wiping means fewer micro-scratches over time. Those scratches scatter light and make panes look cloudy before their time. Being gentler extends clarity and can delay the itch to replace glass.
Common mistakes that ruin the effect
- Applying to a damp pane dilutes the starch and leaves streaks.
- Using kitchen roll sheds lint; microfibre gives a clean polish.
- Overloading the surface builds a gummy layer. Less is more.
- Buffing too soon removes the film before it settles. Wait a minute.
- Treating hot glass can bake residue. Let the pane cool first.
If you can see smears after polishing, you used too much product or rushed the buff. A second dry buff usually fixes it.
People are swapping tips, not buying gadgets
In kitchens across Picardy, residents are sharing low-cost fixes as energy bills bite. Some pair the potato trick with small changes: pan lids on by default, extractor hoods used for 10 minutes after cooking, and short bursts of cross-ventilation. Each change shaves moisture from the air and reduces fog episodes.
A simple checklist for clearer panes and healthier air
- Keep indoor humidity near 40–60%. A £10 hygrometer helps track it.
- Use lids on simmering pots; that can cut steam release by up to 50%.
- Run the extractor on a low setting longer rather than on high for one minute.
- Wipe window sills dry after heavy cooking to deter mould.
- Open a window for five minutes to swap stale, moist air for fresh.
What to try if you do not have a potato
A tiny drop of diluted washing-up liquid works in a pinch. Spread it thinly, let it settle, then polish until the glass gleams. A pea-sized dab of shaving foam also shifts the contact angle and can last a couple of weeks. As with starch, the key is restraint and patience with the buff.
Questions readers keep asking
- Will it leave a greasy look? No. If you polish to a shine, the layer is invisible. Any haze means you need another dry buff.
- Is it safe for timber frames? Yes, if you avoid rubbing the sealant and wipe any residue from the frame straight away.
- Does it harm the glass? No. You are not abrading the surface. Avoid scouring pads and stick to soft cloths.
- How long does one treatment last? In most busy kitchens, two to three weeks in winter. Lighter use stretches that to a month.
- Can I use it on bathroom mirrors? Yes. The same film reduces mirror fog after showers. Apply thinly, polish well.
Extra context that helps the trick shine
Condensation is a moisture problem first and a visibility problem second. If fog is heavy even after treatment, target the source. A lid on every boiling pot, a pan-sized burner match, and a gentle extractor run reduce water vapour at the root. Small gaps behind furniture near exterior walls also prevent cold spots that breed damp. These changes pair neatly with the potato film and keep frames dryer.
For curious tinkerers, try a simple test. Treat one half of a pane, leave the other half bare, then boil a litre of water for five minutes. Watch how droplets bead on the untreated side while the treated side forms a flatter film. The difference is immediate, and it gives you a feel for how thin the application should be next time.
