How to whiten socks: 5 methods that tackle grey soles

After a few weeks it is always the same story: the leg is still bright, the sole has turned grey and the socks look dull overall. If you are wondering how to whiten socks, you need neither chlorine bleach nor expensive special products – but you do need the right order: pre-treat, soak, wash warm enough and dry them properly.

In winter many of us pad around the flat in socks on parquet and tiles, and the soles pick up dust and dirt. These five methods bring the brightness back, and a few habits help keep it that way.

Why white socks turn grey

A sock takes weight, friction and sweat all day long. On the sole, dirt from outside is added: dust from the floor and particles rubbed off the inside of your shoes. Skin oil acts like glue and holds these fine particles in the fibres. At 30 °C and with a detergent that contains no bleach, this film does not come out completely, so the sole gets a little darker with every wash.

Other causes affect the whole sock:

Our guide to laundry detergent dosage shows how to match the amount to the water hardness in your commune.

1. Pre-treat the soles with gall soap

The single most effective step against grey soles is targeted pre-treatment. Gall soap dissolves grease and ground-in dirt; you will find it in supermarkets and chemists.

1. Wet the sole thoroughly with warm water.
2. Rub the soap in firmly – on the outside, and on the inside too if the socks are very sweaty.
3. Work it in with an old toothbrush or by rubbing the sole against itself.
4. Leave it for 15 to 30 minutes without letting the soap dry out.
5. Move straight on to soaking, or wash as usual.

No gall soap to hand? Plain curd soap will do. Like washing soda and bicarbonate of soda, it is one of the simple household remedies that the Swiss consumer protection foundation (Stiftung für Konsumentenschutz) recommends instead of many specialist cleaners.

2. Soak them overnight in washing soda

If the socks look grey all over, a soak is the next step. Washing soda (sodium carbonate) is alkaline and dissolves grease and sweat residue from cotton.

1. Fill a bucket or the washbasin with warm water.
2. Dissolve the washing soda in it according to the instructions on the pack.
3. Submerge the socks completely and leave them to soak for a few hours or overnight.
4. Wring them out and wash them in the machine as usual.

Bicarbonate of soda (baking soda) is much milder and is only enough for socks that are slightly greyish. Neither is suitable for wool or silk: woollen socks belong in the wool cycle with a wool detergent.

3. Oxygen bleach instead of chlorine

If washing soda is not enough, use oxygen bleach based on sodium percarbonate, often sold as stain remover powder. It releases oxygen in water, brightens cotton and is gentler than chlorine. It only works properly in warm water – the exact temperature and amount are on the pack.

• As a soak: dissolve it as directed and leave the socks in it for a few hours.
• In the machine: add it alongside your detergent, as the manufacturer specifies.

The triangle on the care label tells you whether bleaching is allowed at all: an empty triangle permits any bleach, one with two diagonal lines only oxygen bleach, and a crossed-out one none at all. GINETEX explains every symbol in its care symbols index.

Chlorine bleach (known in Switzerland as Javel water) is off limits for socks: almost all of them contain elastane, and chlorine makes this fibre brittle. The cuffs go baggy and a yellow tinge often remains.

4. Wash hot if the label allows it

The number in the wash tub symbol on the care label is the maximum temperature. Many cotton socks can take 60 °C, while pairs with a lot of synthetic fibre or elastane often stop at 40 °C.

• Detergent: universal washing powder usually contains oxygen-based bleach, which works better at higher temperatures. Colour and liquid detergents usually contain no bleach, so they are only second best for light-coloured socks.
• Inside out: skin flakes and sweat sit on the inside and rinse out better this way.
• Only with light colours: white towels, bed linen and underwear go well together; jeans and darks do not.

SwissEnergy (EnergieSchweiz) recommends low temperatures of 20 to 30 °C, eco programmes and full loads for everyday laundry. So wash your socks cool most of the time and treat them to a 60 °C cycle only now and then – ideally together with towels and bed linen so the drum is well filled.

5. Dry white socks in the sun

Sunlight has a slight bleaching effect on light cotton. Hang your socks outdoors if you can, on the balcony or in the garden. In winter the effect is weaker, but a sunny day still helps. Coloured laundry, on the other hand, belongs in the shade, because sunlight fades it.

• Check before the tumble dryer: if the sole is still grey, repeat the treatment first – heat can set leftover dirt.
• Go easy on elastane: if the label allows tumble drying, choose the low-heat setting.

Common mistakes

• Washing them with jeans and darks: loose dye settles in the light fibres. Our guide on colour run explains what to do after a dye mishap.
• Chlorine against grey: elastane turns brittle and yellowing looms. See also how to whiten yellowed clothes.
• Always washing cold with liquid detergent: without bleach and a little warmth, the greasy film stays in the sole.
• Vinegar and baking soda together: it fizzes impressively, but the two neutralise each other and the effect fizzles out.

Priority Clean editorial teamOur cleaning team from Alberswil, Canton of Lucerne, shares hands-on experience from move-out, house, office and window cleaning across Central and Northwestern Switzerland.