Wool
A protein fibre. The wool industry body advises against bleach of any kind and against enzyme detergents, and heat with agitation felts it irreversibly.
What not to do
Sodium hypochlorite (chlorine bleach) is unsafe on Wool
Unsafe
Do not do this. The risk is established, and it is described below.
The wool industry body advises against bleach of BOTH kinds — this record was widened in Sprint 2 when its page was actually read.
Precautions
- Check the manufacturer's instructions
Why we say this
Strongly supported
Directly stated by the industry body for the fibre. The mechanism is cited separately as background because Woolmark gives no account of keratin chemistry anywhere on its pages — CleaningHQ's explanation of why is its own interpretation.
Sources
Best detergent to use when washing wool
The Woolmark Company · Trade or professional body
Relied on for: That bleach must never be used when washing wool, chlorine-based or oxygen-based. (states this directly)
Verification: a person has read the passage relied on.
Read on — The detergent-selection guidance and its bleach and enzyme statements. Supports a wider statement — our claim was widened. CleaningHQ had recorded wool as bleach-sensitive with respect to CHLORINE bleach only, following the Sprint 1 verification target. Woolmark's position is wider, and the wool record, the oxygen-bleach agent record and the laundry relationships were all widened to advise against oxygen bleach on wool as well. Separately, because the page supplies no mechanism, CleaningHQ's keratin-hydrolysis explanation is now cited to this source as background only and rests on protein chemistry from elsewhere.
Kirk-Othmer Encyclopedia of Chemical Technology
John Wiley & Sons · Reference work
Relied on for: That hypochlorite is an aggressive oxidant which attacks protein fibres, and that keratin is a protein. (background and mechanism only)
Verification: the work exists and is described correctly. Nobody has yet read the specific passage.
Last reviewed by a person on .
Sodium percarbonate (oxygen bleach) is unsafe on Wool
Unsafe
Do not do this. The risk is established, and it is described below.
ADDED IN SPRINT 2. Oxygen bleach is widely believed to be the wool-safe alternative to chlorine bleach. The wool industry body advises against it too.
Precautions
- Check the manufacturer's instructions
Why we say this
Supported
This edge exists only because a source was read. CleaningHQ had recorded wool as chlorine-bleach-sensitive and would have gone on implying that oxygen bleach was the safe substitute — which is exactly what the colour-safe marketing around percarbonate encourages. One reading reversed it.
Sources
Best detergent to use when washing wool
The Woolmark Company · Trade or professional body
Relied on for: That bleach must never be used when washing wool, either chlorine or oxygen based, and that detergents containing bleaches should be avoided. (states this directly)
Verification: a person has read the passage relied on.
Read on — The detergent-selection guidance and its bleach and enzyme statements. Supports a wider statement — our claim was widened. CleaningHQ had recorded wool as bleach-sensitive with respect to CHLORINE bleach only, following the Sprint 1 verification target. Woolmark's position is wider, and the wool record, the oxygen-bleach agent record and the laundry relationships were all widened to advise against oxygen bleach on wool as well. Separately, because the page supplies no mechanism, CleaningHQ's keratin-hydrolysis explanation is now cited to this source as background only and rests on protein chemistry from elsewhere.
Last reviewed by a person on .
Sodium carbonate is unsafe on Wool
Unsafe
Do not do this. The risk is established, and it is described below.
Precautions
- Check the manufacturer's instructions
Why we say this
Supported
Labelled as interpretation because the wool body advises against heavy-duty detergents generically rather than naming sodium carbonate. The inference from 'avoid strongly alkaline products' to 'avoid this strongly alkaline product' is sound and is shown as an inference.
Sources
Best detergent to use when washing wool
The Woolmark Company · Trade or professional body
Relied on for: That heavy-duty detergents are advised against for wool in favour of a mild or neutral detergent with a relatively neutral pH. (cleaninghq's interpretation of what it says)
Verification: a person has read the passage relied on.
Read on — The detergent-selection guidance and its bleach and enzyme statements. Supports a wider statement — our claim was widened. CleaningHQ had recorded wool as bleach-sensitive with respect to CHLORINE bleach only, following the Sprint 1 verification target. Woolmark's position is wider, and the wool record, the oxygen-bleach agent record and the laundry relationships were all widened to advise against oxygen bleach on wool as well. Separately, because the page supplies no mechanism, CleaningHQ's keratin-hydrolysis explanation is now cited to this source as background only and rests on protein chemistry from elsewhere.
Kirk-Othmer Encyclopedia of Chemical Technology
John Wiley & Sons · Reference work
Relied on for: That alkaline hydrolysis degrades protein. (background and mechanism only)
Verification: the work exists and is described correctly. Nobody has yet read the specific passage.
Last reviewed by a person on .
Precautions
- Check the manufacturer's instructions
In detail
Wool is keratin, a protein, and nearly every rule about washing it follows from that. Protein is hydrolysed by alkali, so strongly alkaline detergents and laundry boosters degrade the fibre rather than only stripping soil from it. Biological detergents contain proteases — enzymes whose purpose is to break down protein stains — and those enzymes do not distinguish between a protein stain and a protein fibre; the wool industry body advises against them by name. On bleach its position is wider than is often assumed and wider than CleaningHQ itself recorded before checking: not chlorine bleach only, but chlorine and oxygen bleach alike, and detergents containing either. Separately from chemistry, wool fibres carry overlapping surface scales; under the combination of heat, moisture and mechanical agitation those scales interlock and the fabric felts, shrinking permanently. This is why wool washing guidance is as concerned with temperature and agitation as with what is in the water, and why the damage cannot be reversed once done. Garments certified as machine-washable are engineered for repeated washing on a wool cycle; that certification is a property of the garment, not of wool.
Properties
Sensitivity
- Acids
- Not known
- Alkalis
- Recorded
- Chlorine bleach
- Recorded
- Heat
- Recorded
- Abrasion
- Recorded
- Porous
- Recorded
“Not known” means CleaningHQ has not established this, not that the material is unaffected.
What works
Wool detergent is safe on, in specific conditions, Wool
Safe only in specific conditions
This is only appropriate within specific limits. Outside those limits, CleaningHQ makes no claim.
Only within these limits:
- A mild or neutral detergent, with no enzymes and no bleach of either kind
- Wool cycle at 40°C, or hand wash at around 30°C
- Gentle agitation only — do not rub, pull or wring
- Dry flat unless the garment's own care claim states it may be tumble dried
The garment's care label governs. Machine-washability is a property of the individual garment rather than of wool.
Precautions
- Check the manufacturer's instructions
Why we say this
Supported
The laundry vertical's positive clearance, resting on two pages of the wool industry body's guidance that were read during this sprint. Every limit above is quoted from one of them.
Sources
Best detergent to use when washing wool
The Woolmark Company · Trade or professional body
Relied on for: That a mild neutral detergent is recommended for wool and that heavy-duty, enzyme-containing and bleach-containing detergents are to be avoided. (states this directly)
Verification: a person has read the passage relied on.
Read on — The detergent-selection guidance and its bleach and enzyme statements. Supports a wider statement — our claim was widened. CleaningHQ had recorded wool as bleach-sensitive with respect to CHLORINE bleach only, following the Sprint 1 verification target. Woolmark's position is wider, and the wool record, the oxygen-bleach agent record and the laundry relationships were all widened to advise against oxygen bleach on wool as well. Separately, because the page supplies no mechanism, CleaningHQ's keratin-hydrolysis explanation is now cited to this source as background only and rests on protein chemistry from elsewhere.
Wool care: how to wash wool, and caring for wool
The Woolmark Company · Trade or professional body
Relied on for: That wool is washed on a gentle wool cycle at 40°C or by hand at around 30°C, that garments should not be rubbed or wrung, and that drying flat is recommended unless the care claim permits tumble drying. (states this directly)
Verification: a person has read the passage relied on.
Read on — The "How to wash wool" page (machine and hand washing, drying) and the "Caring for wool" page (tumble drying, flat drying, detergent). Supports a narrower statement — our claim was reduced. These pages support the temperature, agitation and drying guidance but NOT the bleach position, which CleaningHQ had attributed here in Sprint 1. That claim was moved to woolmark-detergent-guidance, where the statement actually appears. CleaningHQ's felting explanation is not supported by Woolmark at all and is now carried by the fibre-science record as an interpretation rather than cited here.
Last reviewed by a person on .
Isopropyl alcohol is safe on, in specific conditions, Wool
Safe only in specific conditions
This is only appropriate within specific limits. Outside those limits, CleaningHQ makes no claim.
Sprint 29. A positive conditional for a solvent on a protein fibre, which the register did not hold.
Only within these limits:
- Diluted — three parts surgical spirit to one part cold water for red wine, fruit and fruit juice
- Equal parts warm water and surgical spirit for alcoholic drinks
- Applied by dabbing on a lint-free cloth, working from the edge towards the centre, never rubbing
- Only after rinsing and a dilute detergent solution have been tried first
- Followed by a wash in an approved wool detergent
The wool body names surgical spirit in five of its ten stain entries and dilutes it in every one. It is the second step throughout, never the first.
Precautions
- Test on an inconspicuous area first
- Ventilate the area
Why we say this
Supported
The fibre body's own guide, naming the dilution each time. Recorded as conditional rather than cleared because every appearance is diluted, is a second step, and is followed by washing.
Sources
The Woolmark Company · Trade or professional body
Relied on for: That surgical spirit diluted three to one with cold water treats persistent red wine, fruit and fruit juice marks on wool; that equal parts warm water and surgical spirit treats alcoholic drinks; and that it is used for grass and for ballpoint ink, always after a first step and always followed by a wash. (states this directly)
Verification: a person has read the passage relied on.
Read on — Sprint 29 read all ten stain entries plus the general method. Earlier sprints had read the general method and two entries - oily stains and blood - out of ten. Supports a wider statement — our claim was widened. The register had read two of ten entries and treated the source as done. The red wine entry is the one that matters most: two accepted intents about red wine on a wool carpet had been partial for want of a fibre-specific procedure, and it was on this page throughout. Also new: the salt-first route for egg and milk, the bicarbonate route for black coffee, the do-not-let-it-dry rule for ink, and the instruction to tell a dry cleaner what has already been applied - the only handover instruction in the register.
Last reviewed by a person on .
Wool detergent is safe on, in specific conditions, Wool
Safe only in specific conditions
This is only appropriate within specific limits. Outside those limits, CleaningHQ makes no claim.
Only within these limits:
- A DILUTE solution, in TEPID water — not hot
- Blot or scoop the excess first with white tissue or an absorbent towel
- Work from the edge of the mark towards the centre, without rubbing
- For oily stains, only AFTER a solvent has been applied and allowed to evaporate
The wool body's stain method. The conditions are as much about order and technique as about the agent.
Precautions
- Test on an inconspicuous area first
- Check the manufacturer's instructions
Why we say this
Strongly supported
The fibre's own trade body, specifying agent, dilution, temperature and sequence.
Sources
The Woolmark Company · Trade or professional body
Relied on for: That treatment uses a dilute solution of approved wool detergent in tepid water, that excess is scooped or blotted first with white tissue, that the stain is worked from edge to centre without rubbing, and that oily stains take solvent first with evaporation before water-based treatment. (states this directly)
Verification: a person has read the passage relied on.
Read on — Sprint 29 read all ten stain entries plus the general method. Earlier sprints had read the general method and two entries - oily stains and blood - out of ten. Supports a wider statement — our claim was widened. The register had read two of ten entries and treated the source as done. The red wine entry is the one that matters most: two accepted intents about red wine on a wool carpet had been partial for want of a fibre-specific procedure, and it was on this page throughout. Also new: the salt-first route for egg and milk, the bicarbonate route for black coffee, the do-not-let-it-dry rule for ink, and the instruction to tell a dry cleaner what has already been applied - the only handover instruction in the register.
Last reviewed by a person on .
Why
- Wool is explained by Fibre swelling and shrinkage
Partial. The swelling account applies; wool felting is a separate mechanism no source held explains.
Related
Aftercare and prevention
- Solvent wiping requires the aftercare Wool
The aftercare is a wait: the solvent must fully evaporate before any water-based treatment follows.
Hacks and claims involving this
- Oxygen bleach is the wool-safe bleach Does not work
- Natural cleaning products are safer Does not work
- Hotter washes clean better Disputed
- Bicarbonate of soda absorbs odours Plausible mechanism, untested in this application
- Dry-clean-only labels are just the manufacturer being cautious Does not work
- Hot water for a blood stain Does not work
- A stronger solution cleans better Does not work
- Freezing chewing gum off with ice Unresolved
- Washing silk at home Disputed
- Using laundry detergent on a carpet stain Does not work
- Drying wool flat rather than hanging it Supported
- The care label allows oxygen bleach even when it bans chlorine Does not work
- The dots on a care label are just a rough guide Does not work
- Washing cold prevents shrinking Disputed
- A stain method that works on cotton works on anything Does not work
- Press harder to get the creases out Does not work
- Bleach ruins outdoor fabric Does not work
When the obvious answer is wrong
What should I use on red wine spilled on a wool carpet or jumper?
Wool is a protein fibre and oxidising bleaches attack it directly, degrading the keratin rather than the stain sitting on it. The damage is structural and it is not a mark that can be cleaned off afterwards: the fibre is weakened, and on a carpet the affected area wears differently from everything around it. The wool body approaches this from the other side, warning that methods aimed primarily at cotton or synthetic garments are not all suitable for wool.
A different kind of treatment works: Change the mechanism from oxidation to dilution and dissolution, and respect the order. The wool body gives red wine, fruit and fruit juice their own entry and its sequence is three steps. First RINSE WITH CLEAN WATER — before any product, because wine is water-soluble while it is fresh and the cheapest removal happens then. Second, a DILUTE solution of an approved wool detergent. Third, and only where the mark persists, THREE PARTS SURGICAL SPIRIT TO ONE PART COLD WATER. Technique carries the rest and is stated for every entry on the page: scoop or blot the excess immediately with white tissue or an absorbent towel, work from the EDGE towards the centre, and dab rather than rub. Finish with a wash in an approved wool detergent. Where the label permits dry cleaning and the mark survives, tell the cleaner what the stain is AND what has already been applied to it — a treated stain is a different problem from an untreated one.
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.
A different kind of treatment works: Change the mechanism from saponification to dissolution, and respect the order. The wool body's instruction for oily or greasy stains is that they are best treated with SOLVENTS FIRST, and that the solvent MUST BE ALLOWED TO EVAPORATE before any water-based treatment is subsequently carried out. That waiting step is the part most likely to be skipped and it is stated explicitly. The water-based stage that follows is a dilute solution of an approved wool detergent in tepid water — dilute rather than strong, tepid rather than hot. Technique carries the rest: scoop or blot the excess quickly with white tissue or an absorbent towel, work from the edge of the mark towards the centre, and do not rub. Where the mark survives that, the honest next step is professional cleaning rather than a stronger alkali.
Sources for this page
Sources
Best detergent to use when washing wool
The Woolmark Company · Trade or professional body
Relied on for: That bleach must never be used on wool, chlorine-based or oxygen-based, and that heavy-duty and enzyme-containing biological detergents should be avoided in favour of a mild neutral detergent. (states this directly)
Verification: a person has read the passage relied on.
Read on — The detergent-selection guidance and its bleach and enzyme statements. Supports a wider statement — our claim was widened. CleaningHQ had recorded wool as bleach-sensitive with respect to CHLORINE bleach only, following the Sprint 1 verification target. Woolmark's position is wider, and the wool record, the oxygen-bleach agent record and the laundry relationships were all widened to advise against oxygen bleach on wool as well. Separately, because the page supplies no mechanism, CleaningHQ's keratin-hydrolysis explanation is now cited to this source as background only and rests on protein chemistry from elsewhere.
Wool care: how to wash wool, and caring for wool
The Woolmark Company · Trade or professional body
Relied on for: That wool is washed on a gentle wool cycle at 40°C or by hand at around 30°C, and that garments are recommended to be dried flat unless the care claim permits tumble drying. (states this directly)
Verification: a person has read the passage relied on.
Read on — The "How to wash wool" page (machine and hand washing, drying) and the "Caring for wool" page (tumble drying, flat drying, detergent). Supports a narrower statement — our claim was reduced. These pages support the temperature, agitation and drying guidance but NOT the bleach position, which CleaningHQ had attributed here in Sprint 1. That claim was moved to woolmark-detergent-guidance, where the statement actually appears. CleaningHQ's felting explanation is not supported by Woolmark at all and is now carried by the fibre-science record as an interpretation rather than cited here.
Kirk-Othmer Encyclopedia of Chemical Technology
John Wiley & Sons · Reference work
Relied on for: That keratin is a protein and that proteins are hydrolysed by alkali and by protease enzymes. (background and mechanism only)
Verification: the work exists and is described correctly. Nobody has yet read the specific passage.
What CleaningHQ cannot answer yet
These are recorded questions about this subject that we have not yet researched to a standard we would publish.
- Compare drying methods for fabric longevity
- Assess machine washing of tailored wool
Last reviewed by a person on .