Cleaning a kitchen

Where the obvious answer is wrong

Cases where the treatment that removes the problem is the treatment that ruins the surface it is on.

• Can I use oven cleaner or a strong degreaser on aluminium?

  Aluminium is amphoteric — attacked by strong bases as well as by strong acids. The alkali dissolves the protective oxide film and then the metal beneath, leaving a dull grey or blackened surface that is not a deposit and cannot be cleaned off. There is a second consequence that is a safety matter rather than a cosmetic one: a US state hazardous substance fact sheet records that sodium hydroxide reacts with metals including aluminium to form flammable and explosive hydrogen gas, which is not what anybody expects from cleaning an oven tray in a confined space.

• Can I use oven cleaner on the burnt-on mess in my self-cleaning oven?

  The manufacturer prohibits it in absolute terms: no commercial oven cleaner or oven liner protective coating of any kind should be used in or around any part of the oven. The mechanism is delayed rather than immediate. RESIDUE FROM OVEN CLEANERS WILL DAMAGE THE INSIDE OF THE OVEN WHEN THE SELF-CLEAN CYCLE IS USED — so the harm happens later, at pyrolytic temperature, to whatever the cleaner left behind. Someone who sprays, wipes and sees nothing wrong has not shown the practice is safe; they have postponed the test. The same guide notes that even soap left on the liner causes additional stains when the oven is heated.

• Can I leave a cast iron pan to soak to get the burnt-on food off?

  Cast iron is bare iron protected by a layer of polymerised oil, and that protection is defeated by water rather than by scrubbing. The manufacturer's wording is blunt: SOAKING CAST IRON IN WATER IS A RECIPE FOR RUST. It extends the same warning to cookware left in the sink to soak, put in the dishwasher, allowed to air dry, or left in a moisture-prone environment — and states that a dishwasher will remove the seasoning and likely cause rust. The failure is not the burnt food coming off. It is that the pan is left in prolonged contact with the one thing its finish exists to keep off it.

• What should I use on a greasy mark on a wool jumper?

  Wool is a protein fibre, and the mechanism that converts fat to soap also hydrolyses protein. A strong alkali therefore attacks the garment on the same chemistry it uses on the stain, and the damage is to the fibre rather than to its appearance — it is not a mark that can be cleaned off afterwards. The wool body approaches the same problem from the other end, warning that methods primarily aimed at garments made from cotton or synthetic fibres are not all suitable for wool, and specifying a dilute wool detergent in TEPID water rather than anything stronger or hotter.

• How do I get grease off a vinyl seat without leaving a mark on it?

  The coated-fabric trade body classifies vinyl, polyurethane and silicone coated fabrics as SOFT-SURFACE materials despite their being smooth and non-permeable, and states that hard-surface cleaners, sanitizers and disinfectants are not intended for soft surfaces and could damage them. It then names hand sanitisers among the substances that STAIN coated fabric. So the alcohol wipe that removes the grease is on the list of things that mark the seat, and the mark it leaves is not a soil sitting on the coating that can be wiped off again.

Assessed and found wanting

Widely repeated techniques in this area that the evidence does not support, or supports only in part.

• Sealing stone makes it stain-proof

  Does not work

  The stone trade's own guidance is unusually blunt about this: a sealer is a repellent, not a seal, and sealing does not make stone stain-proof.

• Natural cleaning products are safer

  Does not work

  Natural describes where something came from and predicts nothing about what it does. The UK regulator lists this belief among the myths it exists to correct.

• Mixing vinegar and bicarbonate of soda

  Does not work

  The most popular cleaning combination on the internet, and the two ingredients largely cancel each other out. Both are useful — separately.

• Steel wool for stubborn marks on stainless steel

  Does not work

  It works in the moment and creates the next problem. The embedded carbon steel particles it leaves behind are what later look like the stainless steel rusting.

• Leaving bleach in the sink overnight

  Does not work

  Named and advised against by the stainless steel trade association, and it is also how two of the documented chlorine gas exposures began.

• Vinegar as an all-purpose cleaner

  Disputed

  Genuinely excellent at one job and promoted into a universal one. The surfaces it is most often recommended for online include several it permanently damages.

• Hotter washes clean better

  Disputed

  True of the chemistry and false as advice. Temperature is one of four variables, and it is the one most fabrics constrain hardest.

• Never use soap on cast iron

  Does not work

  Among the most confidently held rules in domestic cooking, and the manufacturer contradicts it outright. The prohibition outlived the soap it was formed around.

• Steam mops are safe on sealed wood floors

  Does not work

  Steam mops are marketed for wood floors and sold in the flooring aisle. The wood flooring trade association rules them out entirely.

• Scrub a carpet stain to get it out

  Does not work

  The instinctive response to a spill, and the one the carpet trade association specifically prohibits. Scrubbing damages the carpet itself.

• Using a stone cleaner on a quartz worktop

  Does not work

  It looks like stone, it is sold as stone, and the manufacturer explicitly tells you not to use the products made for stone on it.

• Oven cleaner for a stubborn worktop mark

  Does not work

  Reaching for the strongest thing in the cupboard when a mark will not shift. On engineered quartz the manufacturer prohibits it outright.

• A stronger solution cleans better

  Does not work

  The trade body that publishes carpet stain procedures puts this in capitals: NEVER USE A STRONGER CONCENTRATION. That is a claim about damage, not about thrift.

• Steam mopping a laminate floor

  Does not work

  The European laminate producers' technical bulletin has one categorical sentence and this is it: steam cleaners are not suitable for use with any type of laminate floor.

• Washing silk at home

  Disputed

  The professional body lists five specific ways it goes wrong. It also has an obvious commercial interest in saying so, and both facts belong in the answer.

• Scraping glass clean with a razor blade

  Does not work

  The glass industry excludes blades and metal scrapers from routine cleaning outright, and the scratches may only become visible months later at the right sun angle.

• Saddle soap and mink oil for leather

  Does not work

  The two products most associated with looking after leather are both on the trade body's prohibited list, and for the same reason: the finish changed.

• Washing-up liquid on leather

  Does not work

  The gentle-sounding option. The leather trade lists soap and dish detergent among caustic household cleaners not to use on it.

• Using oven cleaner in a self-cleaning oven

  Does not work

  The manufacturer prohibits it outright, and gives a mechanism nobody expects: the residue is what damages the oven, and it does so on the next self-clean cycle.

• All-purpose cleaner on a vinyl floor

  Does not work

  Named in the prohibition list by the flooring manufacturer, alongside steel wool and solvents — and so are the mops people use.

• Alcohol cleaners are gentle, so they are safe

  Disputed

  Its health rating is 1 and its flammability rating is 3. The hazard people underrate is the one the regulator rates highest.

• Lining hob drip pans with foil

  Does not work

  Saves cleaning, and the manufacturer forbids it with three consequences named: shock, fire or damage to the range.

• Oven cleaner on the grill pan and grid

  Disputed

  One accessory, two parts, opposite instructions. The manufacturer permits oven cleaner on the pan and prohibits it on the grid.

• Food spills on an appliance can wait until you clean

  Does not work

  For acidic spills the manufacturer says immediately, and names the consequence as discolouration rather than dirt.

• A stain method that works on cotton works on anything

  Does not work

  The wool body warns against exactly this, and gives wool a sequencing rule cotton advice does not have: solvent first, allowed to evaporate, only then water.

• Spraying disinfectant instead of cleaning

  Does not work

  Marketed as the thorough option, and it is — against organisms. On a dirty surface it can fail at both jobs at once, because soil shields the organisms it is meant to kill.

• Pouring boiling water down a drain

  Disputed

  Two confident answers circulate and neither survives contact with the evidence. The pipe manufacturer's limit is about volume and duration, not kettles — and the grease comes back anyway.

• Acidic wheel cleaner on alloy wheels

  Disputed

  Sold specifically for the job, and a standards body prohibits every acid it is likely to contain on the finish it is likely to be sprayed on.

• Washing soda as a general-purpose cleaner

  Disputed

  It really is a strong alkaline degreaser, and two of its most-promoted uses are on materials that alkalis attack.

• Using baking powder instead of bicarbonate of soda

  Does not work

  Two different products with almost the same name. One of them already contains the acid that cancels it out, plus a starch that stays behind.

The records

• Oven

  Thing to clean

  Baked-on grease polymerised by heat, in an enclosure containing several materials with conflicting requirements.

• Hob

  Thing to clean

  A hot surface that must be cleaned cold, where the enamel is acid-resistant rather than acid-proof — and the difference is a spill left standing.

• Hob surface

  Component

  Glass-ceramic that must be cleaned cold, except for one deposit that has to be removed while it is still warm.

• Grill

  Thing to clean

  The part of a cooker that carbonises fat by design. The manufacturer excludes oven cleaner from the pan and the grid, and adds a fire warning about foil.

• Kitchen worktop

  Thing to clean

  The surface most likely to be cleaned with the wrong product, because five materials that look similar have five incompatible rule sets.

• Kitchen sink

  Thing to clean

  Usually stainless steel, and the surface in a house most exposed to the two things that damage stainless steel: chlorides and abrasion.

• Sink waste

  Component

  Where the smell actually comes from, and the place two drain products from opposite families can meet each other out of sight.

• Burnt-on food and carbon deposits

  Stain or problem

  Food heated until it carbonised and bonded to the surface. Time and softening do the work; scouring powder does the damage.

• Grease

  Stain or problem

  Fats and oils, which water alone cannot lift. Removed by surfactants, by heat, by solvents, or by alkalis that convert the fat into soap.

• Polymerised oil

  Science

  Heated oil cross-links into a hard varnish. The same reaction gives a cast iron pan its seasoning and an air fryer its brown film.

• Oven cleaner

  Cleaning agent

  A product category built on strong alkali. It works by turning baked-on fat into soap, and it damages aluminium, paint and self-cleaning linings doing it.

• Saponification

  Science

  An alkali reacting with a fat to make soap. It is how soap is manufactured, and it is also how oven cleaner removes baked-on grease.

• Alkali attack on light metals

  Science

  Aluminium, zinc and their alloys are dissolved by strong alkalis as readily as by acids, and the reaction gives off hydrogen.