One bottle, four ingredients, and enough of the formula to adapt it yourself.
~18 min read
Look under your sink and count the bottles. Most households have between six and fifteen, each bought for a single surface, most of them ninety-five per cent water. What is worth noticing is not the cost. It is that nearly all of them are the same few ingredients in different proportions.
Ordinary cleaning is a small number of jobs. You loosen soil so it stops clinging, hold it in a liquid, and carry it away on a cloth. Grease needs one kind of help to let go. Mineral deposits — limescale, hard-water film, the ring in a kettle — need the opposite kind. One bottle covers most of that, and why toxic load is the argument for the swap.
Now the honest part, which is what "most" leaves out. Not an oven interior, which wants a strong alkali and an hour. Not a drain, where the job is contact time in a place a spray cannot hold. Not heavy limescale, which wants the acid neat. Not unsealed stone, a phone screen or a cast-iron pan — each is damaged by it, and [surfaces](#surfaces) says why. And it is a cleaner, not a sanitiser: a board that has had raw chicken on it wants hot water and a product tested for that purpose.
For a 500 mL bottle. The 16 oz bottle sold in the United States is 473 mL, near enough that the same recipe works. Two versions, and you choose one.
| Ingredient | Acid version | Soap version |
|---|---|---|
| Water, ideally distilled or filtered | 440 mL | 470 mL |
| Distilled white vinegar, 5% acidity | 60 mL — 4 tablespoons | none |
| Plant-based liquid soap | none | 5 mL — 1 teaspoon |
| Essential oils | 20–30 drops total | 20–30 drops total |
| Which works out as | about 0.6% acetic acid | about 1% soap |
The acid version is for mineral soil: limescale on a tap, film on a shower screen, soap scum. The soap version is for greasy soil: a hob, a splashback, a fridge door. If you want only one bottle, make the soap version — grease is the more common problem in more rooms.
Never both at once
Vinegar and soap in one bottle cancel each other out. The acid strips the soap of what makes it dissolve in water, and the soap falls out of solution as white curds. Both are spent doing it, and you are left with cloudy water carrying a film of fat — dirtier surfaces, not cleaner ones.
Shake it gently before every use. Separation is normal — an oil that will not dissolve in water is behaving exactly as an essential oil should.
Photograph to come
One batch laid out on a worktop before it goes in: empty amber bottle with the trigger off, jugs of water and vinegar, a teaspoon of soap, oil bottles uncapped. Real kitchen, real light, nothing styled.
Water — the carrier
Between 88 and 94 per cent of the bottle, and not a filler. It spreads a tiny quantity of active ingredient over a square metre of worktop, holds the soil once it lets go, and leaves with it on the cloth. Distilled or filtered if you can: tap water carries calcium and magnesium, which spot glass and form the grey film on a bath.
Acetic acid — the vinegar
Shop vinegar at 5% sits near pH 2.4; diluted here the spray lands around pH 3. Limescale is calcium carbonate, and acetic acid converts it to calcium acetate, which dissolves, plus a little carbon dioxide — the faint fizz on a scaled tap. What it does not do is touch grease. On fat, vinegar is water with a smell.
A surfactant — the soap
Surface-active agent, and the name describes the molecule. One end is a long hydrocarbon tail that sits comfortably in oil and will not tolerate water; the other is a charged head that wants water and will not tolerate oil. On a greasy surface the tails bury themselves in the grease and the heads stay out, so the smear of fat ends up wrapped in a shell of water-loving heads — a micelle — and now behaves like something water can carry. That is why a cloth and plain water leave a hob greasy and a cloth with a little soap does not. Surfactant also drops water’s surface tension from about 72 to nearer 30 millinewtons per metre, so the spray wets a surface instead of beading off it.
The oils
The citrus oils bring limonene, a real solvent on greasy and sticky soil. The herb and tree oils bring the constituents they are known for on surfaces. And the bottle smells of its own ingredients rather than of a fragrance added on top.
No preservative — which decides everything else
Every commercial spray has a preservative system, because the bottle is mostly water and water is a medium things grow in. Yours has none, and a homemade preservative is a worse idea than a short shelf life. So: small batches, used up and remade. A commercial bottle lasts a year because of the chemistry you are leaving out.
Diagram to come
Three panels on a worktop cross-section. One: a grease droplet on the surface, water beading beside it. Two: surfactant molecules — filled circle, wavy tail — driving their tails into the grease, heads out. Three: the droplet lifted clear, wrapped in outward-facing heads, leaving on a cloth.
A true soap is the salt of a fatty acid — sodium or potassium joined to a long fatty chain — and the only reason it dissolves is the charge on that head. Acetic acid donates a hydrogen, the hydrogen lands on the head, and a charged carboxylate becomes an uncharged fatty acid that leaves solution at once as white curds. The older kitchen word is curdling, and it is how lemon juice curdles milk. A synthetic plant-derived detergent is not a carboxylate salt and does not do this — but an acid too dilute to strip scale and a detergent at the wrong pH is still a bottle not worth making.
Any oil makes a bottle smell pleasant. A smaller number pull their weight. Which products you can buy varies by country, so if something here is not in your market, the chemistry tells you what to substitute.
Lemon — the default
Cold pressed from the peel of Citrus limon, 60 to 75 per cent limonene, which is what makes it first choice for a cleaning spray. It also takes the gum off a price sticker. Lemon has its own lesson.
Wild Orange — more limonene, usually cheaper
Citrus sinensis, also pressed from the peel, 80 to 97 per cent limonene — the highest in the range, and for grease-cutting per drop the strongest choice you have. Also among the cheapest bottles on the shelf. Wild Orange in the library.
Tea Tree — the household standard
Melaleuca alternifolia, steam distilled from the leaf. Its principal constituent is terpinen-4-ol, and the quality standard is high terpinen-4-ol with low 1,8-cineole. Tea Tree has its own lesson.
On Guard — the spiced option
Wild orange, clove bud, cinnamon bark, cinnamon leaf, eucalyptus and rosemary. It smells like a kitchen in winter. It contains hot oils: clove and cinnamon need considerably heavier dilution than the rest of the range, so keep this spray off bare skin and wash your hands afterwards. On Guard covers the blend.
Purify — the one built for this
Citronella, lime, Siberian fir, tea tree and cilantro — the blend made for this job. doTERRA’s own direction is five drops in a spray bottle of water as a surface cleanser. Purify in the library.
The herbs — rosemary, thyme, oregano
Rosemary brings 1,8-cineole, alpha-pinene and camphor. Thyme and oregano are the heavy end: thyme runs on thymol and carvacrol, oregano on carvacrol and thymol, both phenol-dominant, which puts them among the most potent oils in the range. Five drops per bottle rather than twenty, off bare skin, and wear a glove. Oregano explains why phenols need that respect.
One caution covers every citrus oil here, and it matters because a spray lands on your hands. Lemon, lime, wild orange, grapefruit and bergamot are expressed rather than distilled, and expressed citrus oils make skin more reactive to light. After skin contact, avoid direct sunlight and UV for up to twelve hours.
Limonene is a monoterpene: ten carbons, sixteen hydrogens, a ring with a small tail. The formula is the whole story because of what is missing. No oxygen, no hydroxyl group, nothing carrying a partial charge — a pure hydrocarbon, with no meaningful positive or negative end. Water is the opposite: its oxygen pulls electrons from the two hydrogens, so the molecule has a negative end and a positive end, and those ends grip each other. A substance dissolves well in a liquid held together by the same kind of force as its own — the old rule that like dissolves like, which is not a metaphor but a statement about which arrangement costs less energy. To dissolve limonene, water would have to break its own hydrogen-bond network and gain nothing back.
Now look at what is on your hob. Cooking grease is triglyceride: long hydrocarbon chains, overwhelmingly non-polar. Water cannot get into it for the same reason it cannot get into limonene. Limonene can, because the forces between a limonene ring and a fatty chain are the same weak dispersion forces that hold the fat to itself. The same goes for most label adhesives — which is why citrus degreasers are an industrial product category rather than a wellness idea.
All of that describes a liquid meeting a smear of fat on a worktop. It is a property of the surface and it stops there. Dissolving grease on a counter and anything happening inside a body are entirely different questions, and nothing here is a statement about the second.
The same property has a cost, which is why the next section exists. Several common plastics are themselves non-polar, and limonene gets into them the way it gets into grease: it swells the polymer, softens it, and given contact dissolves it. Expanded polystyrene collapses under a drop in seconds. In the fruit this sits in glands beneath the skin of the peel, where an oily resinous layer makes the rind a poor prospect for anything that might eat through it. Terpenes is the lesson on the family it belongs to.
A spray bottle looks like the least interesting decision here. It is not: what you have just mixed is a solvent, and the bottle is made of a material.
Glass, ideally amber or cobalt
Glass is inert — nothing in this recipe touches it. The colour matters for another reason: monoterpenes oxidise on exposure to light and air, limonene faster than most, and the oxidised products are more likely to irritate skin than the fresh oil.
PET or HDPE, if glass is wrong for the room
Recycling codes 1 and 2. Both hold up against a quarter of a per cent of citrus oil for the month or two a batch lasts. Never reuse a bottle that held a commercial cleaner. Choose by the room: glass on a tiled bathroom floor with small children is a bad idea.
Polystyrene, never
Code 6, the brittle plastic that cracks rather than bends. Limonene attacks it visibly: cloudy, then soft, then failed.
The trigger head
Take a fine mist rather than a jet, and check the dip tube reaches the bottom. When you retire a batch, pump warm water through the head: oils gum a valve shut, and a stuck trigger is the usual reason a good bottle is thrown away.
Then the label. Four things: which version it is, which oils and how many drops, the date you made it, and the words "do not mix with any other cleaner".
That matters more than it sounds. Three weeks from now you will not remember whether the bottle in your hand is the acid one or the soap one, and that decides whether it may go near the stone in your bathroom. Someone else will pick it up, and what they do with an unlabelled bottle is the whole problem — the worst case being that they top it up with bleach. Underneath it is a principle: a household that swaps labelled commercial bottles for unlabelled homemade ones has traded one unknown mixture for another. The argument of this course is knowing what is in things.
Diagram to come
Cut-away side view of a 500 mL amber glass spray bottle: dip tube almost to the base, trigger with its nozzle adjustable between mist and jet, and a label panel on the front. The panel must be legible and carry all four fields as filled-in example text, since the point is that a reader copies it. A crossed-out polystyrene bottle beside it as contrast.
Acid for mineral soil, soap for greasy soil, and neither on anything porous, unsealed, seasoned or coated.
| Surface | This spray? | What to do |
|---|---|---|
| Sealed stone, quartz and laminate worktops | Yes — soap version | Everyday use, then plain water and dry. Keep the acid version off quartz. |
| Unsealed or honed stone — marble, limestone, travertine | Never the acid version | Calcium carbonate: the reaction that dissolves limescale dissolves the surface, leaving dull etched patches no polishing takes out. Soap version only. |
| Sealed or oiled wood | Soap version, damp not wet | Spray the cloth and wring it almost dry. Standing water lifts the grain. |
| Glass and mirrors | Yes — the glass variation | Acid version, no soap, very few drops of oil — soap and oil are what streak. |
| Stainless steel — sinks, taps, appliance fronts | Yes — soap version | Wipe along the grain, then dry or it water-spots. Acid is fine on taps, but rinse it off. |
| Screens — phones, laptops, televisions | Never | A screen carries an oleophobic coating a few molecules thick. Acid, solvent and surfactant all strip it, and it does not come back. Dry microfibre only. |
| Cast iron | Never | The seasoning is polymerised oil, and soap and standing water remove it. Hot water, a stiff brush, dry it on the hob, then a thin film of cooking oil. |
| Painted, lacquered or waxed surfaces | Test first | Limonene softens some paints and lifts wax. Spray a hidden corner, leave it an hour, look in good light. If the finish has gone tacky, that surface gets a damp cloth. |
Test any new surface where nobody looks, and give it an hour — most finish damage appears as it dries. When you cannot tell whether a stone is sealed, flick plain water onto it: if it beads, the stone is sealed; if it soaks in and darkens, nothing acidic goes near it.
Grout takes the acid version, but if the tile is natural stone the acid reaches it as it runs down. Bathroom and personal care goes further into that room.
None of these is a different formula — the same two versions with the proportions moved.
Which bottle are you making?
If you are making only one, the kitchen bottle is the most generally useful.
Most of the difference between a bottle that works and one that disappoints is in five habits.
Spray the cloth, not the surface
Whenever overspray matters — near food, near a plugged-in appliance, anywhere a child’s face is at the height of the trigger — put two or three pumps on the cloth and work from there. Spray the surface only when you want it wet and left to sit.
Give it time to work
Spray and wipe in one movement and the only thing cleaning is the cloth. Soap on grease wants thirty seconds to a minute. Acid on limescale wants five minutes and sometimes fifteen, and it must stay wet throughout — the reaction stops the moment the liquid dries. This is the largest single difference between people who find homemade cleaners work and people who do not.
Cleaning and rinsing are two different actions
Cleaning lifts soil off the surface and holds it in the liquid. Leave the liquid there and you have moved the soil around and left it behind along with whatever lifted it. On anything that touches food, wipe with the spray, wipe again with plain water, then dry. A microfibre cloth matters more than the bottle: its split fibres reach into a texture a cotton rag slides over.
Hard water changes the soap version
Hardness is dissolved calcium and magnesium, measured as milligrams of calcium carbonate per litre; above about 120 mg/L water counts as hard. Those minerals react with a true soap to form the insoluble grey film on a bath. If your kettle scales within a fortnight, use distilled or filtered water. The acid version is unaffected.
How long a batch keeps
Soap version, about a month. Acid version, two to three months, because a pH near 3 is an unfriendly place to be. Retire a batch when it goes cloudy or stringy, smells different, or the scent has flattened. Empty it, wash the bottle in hot soapy water, dry it, remake. Never top up a half-empty bottle.
Never mix this with a commercial cleaner
Not in the bottle, not on the surface, not one after the other without rinsing in between. Bleach and an acid release chlorine gas; bleach and ammonia release chloramine. Both happen in seconds, at ordinary concentrations, and both have put people in hospital. If a surface has had a commercial product on it, rinse and dry first.
One last thing, and it is the part people skip. Use it. A perfect bottle that stays under the sink because the shop one is nearer has changed nothing. Put this one where the old one stood. Laundry, dishes and floors is next.
Keep oils away from eyes and inner ears, and out of reach of children — including a finished spray bottle, which looks like every other bottle under the sink. Never spray towards a face. Never mix this spray, or any ingredient of it, with bleach or with an ammonia-based cleaner. Label and date the bottle. If you are pregnant, nursing, under medical care or taking medication, speak to your healthcare practitioner before use. Nothing here is intended to diagnose, treat, cure or prevent any disease.
Lesson 2 of 7 · Clean Home + DIYs