Which cleaner should I use for which type of dirt?

There are five categories of cleaner and each removes one class of soil. Matching them correctly is the difference between five minutes of waiting and an hour of scrubbing.

Difficulty: beginner
Time: 15 min
Read: 4 min
Safety: caution

Short answer

Acid for mineral deposits, alkaline for grease and organic soil, solvent for ink and adhesive, enzymes for protein and food, abrasive only for what is physically stuck on. If you are scrubbing hard, you almost certainly have the wrong category.

Household cleaning products are marketed by room — bathroom cleaner, kitchen cleaner, floor cleaner — which tells you nothing useful. Chemically there are only five things any of them can be doing, and each acts on a different kind of dirt. Choosing by category rather than by label is the single biggest improvement most people can make to how they clean.

Safety

Never combine products from different categories on the same surface without rinsing thoroughly with plain water in between. Bleach with an acid, or bleach with ammonia, releases toxic gas. Ventilate when using anything strong, wear gloves with alkaline degreasers and acids, and test any new product on a hidden area of the surface first.

What you'll need

A degreaser such as washing-up liquid
An acid such as citric acid or descaler
A solvent such as surgical spirit (optional)
A cream cleaner (optional)

Which type of cleaner shifts which type of dirt

Step by step

Identify the soil before you pick a product.Is it a mineral deposit, a fat, a dye, a protein, or something physically baked on? Everything else follows from that answer.
Use an acid for mineral deposits.Limescale, hard water marks, soap scum with limescale in it, rust and urine scale. Citric acid, descaler, white vinegar. Keep them off natural stone, marble and old grout.
Use an alkaline cleaner for grease.Cooking fat, body oils, food residue and general household grime. Washing-up liquid, soda crystals, sugar soap, oven cleaner. Keep strong ones off aluminium, wood and matt paint.
Use a solvent for anything oil-based that water will not touch.Ink, adhesive, wax, tar, oil paint and some make-up. Surgical spirit, white spirit, acetone. Test first — solvents attack plastics and lacquers.
Use enzymes for protein and food.Blood, milk, egg, urine, vomit and food stains in fabric. Biological detergent and enzyme pet cleaners. They need time and they stop working above about forty degrees.
Use an abrasive only for what is physically stuck.Burnt-on residue, heavy stuck soil. Cream cleaner, bicarbonate paste, a non-scratch pad. It works by cutting, so it will scratch anything polished.
Give the product time instead of pressure.Dwell time is what makes the chemistry work. Spray, leave it five minutes, wipe. Almost all scrubbing is compensation for impatience.
Check the surface can take it.Acid on marble etches instantly. Strong alkali on aluminium blackens it. Solvent on acrylic crazes it. The soil decides the category, but the surface can veto it.
Rinse between different categories.Not only for safety but because an acid and an alkali neutralise each other. Rinse with plain water before switching.
Keep a short list rather than a product per room.Washing-up liquid, a cream cleaner, citric acid or descaler, surgical spirit, biological detergent and bicarbonate cover almost every household job between them.

Tips

Soap scum is usually a mix of body fat and limescale, which is why one product rarely clears it. Degrease first, then acid.
If a surface looks clean but feels tacky, there is product residue on it. Rinse with plain water — residue attracts dirt faster than a clean surface does.
The most useful diagnostic question is what the dirt is made of, not where it is. Grease on a wall and grease on a hob need the same thing.

Common mistakes

Reaching for an abrasive first — It is the only category that works by damaging the surface. It removes the soil and a little of what is underneath, so polished, coated and glossy finishes progressively dull.
Using an acidic bathroom cleaner on natural stone — Marble, limestone and travertine are calcium-based and dissolve on contact with acid. The dull etched patch is permanent and needs professional repolishing.

If it doesn't work

Scrubbing hard and nothing happening

Cause: Wrong category of cleaner for the soil — Fix: Identify the soil type and switch category. Mineral deposit needs acid, grease needs alkali, and no amount of effort substitutes.

Surface dulled or etched after cleaning

Cause: Acid on stone, or abrasive on a polished finish — Fix: Not correctable at home for stone. Stop using that product on that surface and test on a hidden area in future.

Cleaner leaves the surface sticky

Cause: Residue not rinsed off — Fix: Wipe with plain water and dry. Reduce the amount of product used.

Soap scum keeps coming back

Cause: Only one half of the problem being treated — Fix: Degrease with washing-up liquid, rinse, then use an acid for the limescale component.

Questions people ask

Do I need a different product for every room?

No. Six products chosen by category cover almost everything. Room-specific products are largely a marketing structure rather than a chemical one.

What is the safest all-rounder?

Washing-up liquid in warm water. It is a mild alkaline degreaser, safe on almost every surface, and it handles the majority of household soil.

Where does a steam cleaner fit?

It is a sixth option that works by heat and moisture rather than chemistry. Excellent on grease and hygiene, useless on limescale, and dangerous on anything heat-sensitive.