How to Wash and Lanolise Wool Nappy Covers

Wool nappy covers work because lanolin in the fibre reacts with urea in urine and turns into a soap, which is why a well-lanolised cover can be aired and reused rather than washed after every change. Wash them only when soiled or smelly, and re-lanolise every two to four weeks.

Publicerad den 14 juli 2026

Always lanolise after washing, never before, since washing takes the lanolin straight back out. Most guides to this are vague. Here are the actual quantities and times.

Key facts

Wash wool covers rarely - when soiled, or when they smell of ammonia after drying.
Lanolise every two to four weeks, or whenever a cover stops repelling.
A soak lanolising uses roughly 20 ml of a lanolin wash product per litre of water, or about 1 to 2 g of pure lanolin per litre.
Soak half an hour to six hours depending on the product, in water at around 30°C.
Lanolin must be fully emulsified before it goes near the wool, or it leaves greasy spots.
Never use a soap-based lanolin product as a leave-on spray.

Why wool covers work at all

Wool holds lanolin, a waxy substance from the sheep's own skin. Urine contains urea. The two react to form a mild soap, which means a cover that has been weed in is, to a degree, cleaning itself as it dries.

That is the whole mechanism, and everything else follows from it. Lanolin is consumed in the process, so it needs replacing. Washing removes it, so washing means re-lanolising. And a cover that has run out of lanolin stops repelling and starts smelling.

When to wash

Less often than instinct suggests.

Air after every use. Hang the cover somewhere with airflow and let it dry completely - usually a few hours. A dry, aired cover goes back on.

Spot-clean anything solid with cool water and a little wool wash.

Wash properly when the cover is soiled, or when it smells of ammonia once dry. For most families with two or three covers in rotation, that works out at roughly every one to three weeks.

Washing more often than that does not make the cover cleaner. It strips the lanolin, which makes the cover leak, which makes you wash it again.

How to wash

Fill a basin with lukewarm water, no more than 30°C.
Add a wool detergent - a small amount. In soft water, use less than the label says.
Submerge the cover and press gently. No rubbing, no wringing, no agitation.
Leave 10 to 15 minutes.
Rinse in water of the same temperature. Sudden temperature changes felt wool; agitation felts wool; detergent alone does not.
Press out water, roll in a towel to absorb more, then dry flat and away from direct heat or sun.

Then lanolise, because you have just removed what makes it work.

How to lanolise, the soak method

This is the proper version, and it is what a cover needs after washing.

With a lanolin wool product: about 20 ml per litre of hot water. Dissolve it in a little very hot water first, stir until the mixture goes milky and uniform, then top up with cool water to your target volume at roughly 30°C.

With pure anhydrous lanolin: 1 to 2 g per litre - about a quarter teaspoon - plus three or four drops of a mild wool detergent as the emulsifier. This matters: lanolin is a wax and will not disperse in water on its own. Dissolve both in a cup of very hot water and shake or stir hard until the liquid is uniformly milky white with no visible globules floating on top. Then dilute.

Then: put the damp cover in, press it under several times so the solution reaches everywhere, and leave it. Half an hour is enough for a top-up; several hours, or overnight, for a full re-proofing after a wash.

Rinse gently in lukewarm water, press out, roll in a towel, dry flat. Allow a full day to dry - a cover that feels dry can still be damp in the seams, and damp wool in a drawer is how you get a smell.

The failure mode to avoid: lanolin that has not fully emulsified floats as droplets and deposits as dark greasy patches on the wool. If you see oily spots on the water surface, keep mixing before the cover goes in.

Spray lanolising, and the mistake to avoid

Sprays are for topping up between soaks, not replacing them, and coverage is patchier.

Use pure lanolin for a spray, not a soap-based wool product. A lanolin wash or impregnation product is typically 15 to 30% soap, because the soap is what carries the lanolin into the fibre. In a soak that is fine - you rinse the soap out afterwards. In a leave-on spray there is no rinse, so you are leaving soap on fabric that sits against a baby's skin all day.

A spray that works:

1 to 2 g pure anhydrous lanolin, about a quarter teaspoon
3 or 4 drops of a mild wool detergent or baby wash
250 ml water

Dissolve the lanolin and the emulsifier in a splash of very hot water, shake until milky with no globules, then top up to 250 ml with lukewarm water. Shake before every use - it separates.

Spray a damp cover, inside out, until evenly misted rather than soaked. Work it in with your fingers. Air dry completely, usually overnight. Damp fabric takes lanolin far more evenly than dry fabric does.

Keep it in the fridge and make small batches. It is water-based with no preservative and will grow mould within a couple of weeks. Discard it when it smells off or looks newly cloudy.

How often, and how to tell

Every two to four weeks is the usual rhythm, but the cover will tell you.

Signs it needs lanolising:

Water sits on the surface less and soaks in more
Damp patches on clothing over the cover
A persistent ammonia smell even after airing
The wool feels dry or slightly crisp rather than soft

Signs you have overdone it:

The cover feels greasy or tacky
Dark patches that do not dry out
A waxy residue on your hands

Over-lanolised covers can be washed and re-lanolised more lightly. It is a recoverable mistake.

Frequently asked questions

How often should I wash wool nappy covers?

Only when soiled or when they smell of ammonia after drying - typically every one to three weeks. Air them between uses instead.

Do I have to lanolise after every wash?

Yes. Washing removes lanolin, which is what makes the cover water-repellent. Wash and lanolise as a single job.

How long should a cover soak when lanolising?

Half an hour to an hour for a top-up, several hours or overnight for a full re-proofing after washing.

Can I use a wool detergent with lanolin instead of lanolising?

Not as a substitute. The lanolin in a detergent is a trace amount dispersed through litres of wash water and mostly drains away. It conditions the fibre; it does not build the layer a nappy cover needs.

Why are there greasy spots on my cover?

The lanolin was not fully emulsified before the cover went in. Mix until the water is uniformly milky with nothing floating, then dilute. Wash and redo it.

Is lanolin safe on a baby's skin?

Lanolin is widely used in products for babies, including nipple creams. Lanolin allergy exists but is uncommon; if your baby has reacted to a lanolin product before, avoid it.