How to care for handwoven wool: washing, felting, moths, storage and rugs

A handwoven wool throw, blanket or rug is built to be used, and wool is a forgiving fibre in daily life. It is far less forgiving of two things: hot, agitated water, which can felt it in a single wash, and clothes moth larvae, which can quietly eat holes in it while it sits in a cupboard.

Both are preventable. Most care for handwoven wool is about doing less: washing rarely and gently, keeping it clean and dry between uses, and looking at it often enough to catch problems early.

If your maker gave you care instructions, follow them, because they know the yarn, the dyes and whether the cloth was finished or treated. What follows is general guidance from wool industry and museum conservation sources, for when you need to understand why.

Key takeaways

• Felting is caused by heat, moisture and agitation acting together on the scales of wool fibres. It is irreversible, so avoid hot water, rubbing and tumble drying.
• When washing is needed, Woolmark recommends hand washing in lukewarm water at about 30°C with a mild detergent, a short soak, rinsing in lukewarm then cold water, and drying flat.
• Clothes moth larvae, not adult moths, do the damage. They feed on keratin and prefer dark, undisturbed places and soiled fabric, so clean wool before you store it.
• The Natural History Museum says freezing at -20°C for a week kills all life stages of clothes moths in a household freezer; English Heritage advises -18°C for at least two weeks.
• Store wool clean, dry and dark, in closed boxes or bags, with white acid-free tissue in the folds, and check it regularly.
• Rugs last longer with regular gentle vacuuming without a beater bar, rotation every year or two, a suitable underlay and no steam cleaning.

Why wool felts

Wool fibres are covered in microscopic overlapping scales. Woolmark explains that when wool is exposed to heat and moisture the scales lift, and with mechanical agitation they lock onto the scales of other fibres in a ratchet-like mechanism. The fibres entangle and the fabric becomes denser and smaller.

A 2019 review in the Journal of Advanced Research by Mohammad Hassan and Christopher Carr describes the same thing: felting happens in the presence of moisture, mechanical action and heat, and it is irreversible. The scales let fibres move in only one direction, which is why repeated rubbing tightens the fabric instead of loosening it. The authors distinguish felting from relaxation shrinkage, which is reversible and can affect any fibre.

Machine-washable wool has been treated to prevent this. Woolmark says shrink-resist technologies modify the scales so they cannot interlock. You cannot see that treatment, so ask your maker whether the yarn in your piece is shrink-resistant before you put it anywhere near a washing machine.

In practice, three habits prevent felting:

• Keep water lukewarm or cool.
• Do not rub, wring or scrub. Press water through the cloth instead.
• Never tumble dry. Heat and tumbling together are exactly the felting conditions.

Washing

Wash only when the piece is actually dirty. Woolmark notes that wool is naturally resistant to stains, odours and creasing, so it needs washing less often than many fabrics; it suggests that wool blankets may only need washing about every three months. Airing a throw outdoors on a dry day and brushing off surface dust often does the job.

When you do wash, Woolmark's hand-wash method is:

1. Turn the item inside out if it has a right side.
2. Use clean, lukewarm water, about 30°C, and a mild, gentle detergent.
3. Let it soak for about ten minutes.
4. Rinse thoroughly in lukewarm water, then again in cold water.
5. Dry flat.

Woolmark advises machine washing only when the item's care label allows it, on a wool cycle (usually a gentle action at 40°C), or a cold or delicates cycle if there is no wool setting.

For older or delicate pieces, the Institute of Conservation (Icon) advises against ordinary detergents and bleach, because detergents contain optical brighteners and enzymes that stay in the fabric. It notes that even soap flakes may be too alkaline for delicate items. That advice is written for historic textiles, but it is a good reason to choose a detergent made for wool.

Drying

Support the wet weight. Lift the piece out of the water in both hands or in a towel rather than by one corner, roll it in a dry towel to press out water, and lay it flat on a clean towel or drying rack, reshaping it as it dries. Icon warns that heat, such as a nearby radiator, can make textiles brittle. Keep drying wool out of direct sun and away from radiators and fires.

Clothes moths

The Natural History Museum (NHM) names two main clothes moth species in UK homes: the webbing clothes moth (Tineola bisselliella), the more common, and the case-bearing clothes moth (Tinea pellionella), whose larvae build protective cases. Adult moths do not feed. The damage is done by the larvae, which feed on keratin, the protein in wool, fur and other natural fibres. The NHM says they prefer low light and soiled fabrics, such as rugs, which give them nutrients and moisture.

The NHM gives the timescales: eggs hatch in 4 to 10 days in summer and up to three weeks in cooler conditions, and larval development takes anywhere from a month to two years depending on conditions. That is why an infestation can go unnoticed for a long time in a cupboard or under a sofa.

Signs to look for

Royal Museums Greenwich lists the signs museum staff look for: irregular holes, frass (insect droppings), and webbing or cocoons. On rugs, check the underside, the edges and anywhere under furniture, where it is dark and undisturbed.

Prevention

• Clean before storing. Dry cleaning or washing kills pests and removes the dirt and moisture larvae need, according to the NHM. Royal Museums Greenwich says dust is the most attractive food for protein-eating insect pests.
• Close it up. The NHM recommends storing garments in airtight bags or containers. Royal Museums Greenwich suggests lidded plastic boxes for wool and silk.
• Vacuum. The NHM says vacuuming carpets and upholstery helps remove infestations. Royal Museums Greenwich suggests checking wardrobes, under furniture, behind curtains and in attics, and cleaning regularly, including behind books and curtains.
• Monitor. The NHM suggests adhesive pheromone traps to monitor adult moths. The Victoria and Albert Museum uses pheromone lures in its galleries, checked monthly, to track webbing clothes moths. Traps show you whether moths are present; they do not deal with larvae already in a rug.
• Look regularly. Icon suggests checking textiles once a month for insects and other problems.

Treatment

The NHM says freezing at -20°C for a week kills all life stages and can be done with a household freezer. Seal the item in a polythene bag first, as the Canadian Conservation Institute advises for freezing other organic materials. Museums use colder, shorter cycles: Royal Museums Greenwich freezes objects at -30°C for 72 hours, but that needs specialist equipment. English Heritage, which runs a clothes moth research programme for its historic houses, gives a more cautious household figure: seal items in freezer bags at -18°C for at least two weeks. It adds that rugs, carpets and upholstery are best treated in a commercial freezer or by a controlled heat process from a reputable company, and that lavender products are not effective on larvae. If your freezer runs at a typical -18°C, follow the longer timing.

The NHM also notes that heating fabric to 49°C for over 30 minutes kills all stages and suggests a washing machine can do it. Be careful with that route for handwoven wool: warm water and machine agitation are the conditions that cause felting. Ask the maker first.

For fabrics that cannot be frozen or washed, the NHM mentions pyrethrin-based insecticide sprays. For anything valuable, old or large, Icon advises isolating the item in polythene and contacting a conservator.

Storage

Icon's guidance for costume and textiles gives the basics:

• Clean, dry and dark. Store textiles in a clean, dry, dark place where you can check them. Relative humidity above 65% encourages mould; heat can make textiles brittle.
• Cover them. Dust is often acidic and attracts moisture and insects, so cover or pack items.
• Pad the folds. Pack in a clean, strong acid-free box with white acid-free tissue underneath and in the folds. Use the largest box you can, to reduce the number of folds.
• Label the boxes so you do not have to unpack everything to find one piece.

The Canadian Conservation Institute (CCI) adds that warmth makes wool lose its natural oils and weakens the yarn, and advises avoiding basements and attics, where temperature and humidity swing.

Rugs and kilims

A handwoven rug on a floor is wearing out by design. The aim is to make that wear slow and even.

Task	What the conservation sources say
Vacuuming	Regularly, on low suction, without a power head or beater bar, in the direction of the pile; also vacuum the back, the underlay and the floor (CCI)
Fragile areas	Vacuum through a mesh screen on low suction, avoid fringes (Icon)
Rotation	Periodically, for even wear (CCI); every year or two (Icon)
Underlay	3–6 mm thick, reaching the edges, not folded; avoid self-adhesive, foam, vinyl, jute and recycled felt (CCI); polyester suggested (Icon)
Light	Keep out of direct sun; blinds help (CCI, Icon)
Spills	Blot straight away with a dry, white absorbent cloth; do not rub; cover and weight until dry (CCI, Icon)
Cleaning	No steam cleaning or shampoos for machine-made carpet on handmade rugs; wet washing is irreversible, so ask a conservator (Icon)
Storage	Roll, never fold, pile outwards and in the direction of the pile, on a wide tube, wrapped in acid-free tissue or cotton (CCI, Icon)

Icon suggests a simple light check: compare the colours on the front with the back. If the front is noticeably faded, the fibres have probably been weakened too.

Kilims are flatweaves rather than piled rugs. The Central Museum of Textiles in Łódź describes the traditional Polish kilim as a two-sided patterned textile, hand woven in plain weave with a woollen weft and usually a linen warp. If yours is two-sided, ask the maker whether it can be turned over as well as round to spread wear.

When to call a specialist

Icon lists the moments to stop and ask a textile conservator:

• stains, old adhesives or tape, or dye that has run;
• tears, holes or loose parts;
• signs of insects, or mould;
• before wet cleaning or dry cleaning anything historic or valuable;
• whenever you are unsure what the materials are.

Icon advises owners not to use adhesives or sticky tape on rugs, even as a temporary repair, and says a conservator should document their work and give an estimate with options before starting. In the UK, Icon keeps a register of accredited conservators. For a recent piece, the maker is the first person to ask: they may be able to repair or re-weave it, and they know what the yarn will tolerate.

Keep the maker's name, the fibre and the care advice with the piece or on a care card, so that anyone cleaning or repairing it later knows what they are dealing with.

Sources

• How to wash wool, Woolmark: hand wash at about 30°C, mild detergent, ten-minute soak, lukewarm then cold rinse, dry flat, machine washing only when the label allows, wool cycle at 40°C, blankets about every three months, wool needs washing less often
• Machine washable wool, Woolmark: scales, heat, moisture and agitation, ratchet-like locking, irreversible felting, shrink-resist treatments modify scales
• A review of the sustainable methods in imparting shrink resistance to wool fabrics, Hassan and Carr, Journal of Advanced Research (2019): felting mechanism, moisture, mechanical action and heat, one-directional fibre movement, felting vs relaxation shrinkage
• Clothes moths identification guide, Natural History Museum: species, larvae do the damage, keratin, preference for low light and soiled fabrics, life cycle timings, freezing at -20°C for a week, heating to 49°C for 30 minutes, cleaning, airtight storage, vacuuming, pyrethrin sprays, pheromone traps
• Understanding clothes moth infestations, English Heritage: webbing clothes moth shuns light, -18°C for at least two weeks, commercial freezing or controlled heat for rugs, lavender not effective on larvae, prevention tips
• Pest control in museums, Royal Museums Greenwich: signs of moth activity, dust as food, freezing at -30°C for 72 hours, lidded boxes, cleaning behind books and curtains
• Unwelcome flying visitors to the Museum, Victoria and Albert Museum: pheromone lures checked monthly for webbing clothes moths, wool textiles attractive to moths
• Costume and textiles, Institute of Conservation: detergents with optical brighteners and enzymes, soap flakes too alkaline, heat and brittleness, mould above 65% RH, monthly checks, acid-free boxes and tissue, when to call a conservator
• Carpets and rugs, Institute of Conservation: light check front vs back, rotation every year or two, polyester underlay, vacuuming through mesh, no steam cleaning or carpet shampoos, wet washing irreversible, rolling not folding, no adhesives, isolating in polythene
• Basic care: carpets and rugs, Canadian Conservation Institute: vacuuming without power head on low suction, periodic rotation, underlay 3–6 mm and materials to avoid, light, heat and wool oils, avoid basements and attics, blotting spills, rolling on a wide tube
• Removing mould from leather (CCI Notes 8/1), Canadian Conservation Institute: sealing items in polyethylene before freezing in a household freezer
• The Phenomenon of the Polish Kilim, Central Museum of Textiles in Łódź: definition of the Polish kilim as two-sided, plain weave, woollen weft, usually linen warp