How to get sweat out of your clothes, for good

Rub in some detergent first.

Wet the underarms and work a little biological detergent into the patch with your fingers.

If it's crusty, an old toothbrush helps.

Biological just means it has enzymes in it, which break down the sweat and oil the yellow is stuck to.

Leave it for 10 minutes so it can loosen everything up before the soak.

Soak it warm with oxygen bleach.

Fill a sink or bowl with water at around 40 degrees, about as hot as a hot bath, unless the care label says cooler.

Stir in the soaking dose from the tub (usually a scoop) until it's fully dissolved.

Then push the underarms right under the water.

The oxygen bleach lifts the colour while the detergent tackles the oil.

And once it's done, the bleach just breaks down into water, oxygen and soda ash.

Leave it for a few hours.

This is the step everyone skips.

Give it 2 to 4 hours, with a swish every now and then.

Set-in yellow needs time in the water to lift, and a quick cycle just doesn't give it long enough.

Don't leave it overnight, though.

The water goes cold and the bleach slows right down, so a second soak beats a longer one.

Wash it warm, then check before you dry it.

Put it straight in the machine with detergent, as warm as the label allows.

Ideally 40 to 60 degrees, because warmer water shifts oil much better.

Then check the underarms before it goes near the tumble dryer or an iron.

If there's any yellow left, heat will bake it in and make it much harder to shift.

Repeat if needed.

Months of buildup can take a couple of goes.

Really old stains might only fade.

But it's worth trying before you bin anything.

Get it out of your bag.

Damp, warm kit scrunched in a bag is exactly what bacteria love.

That's when they start turning the oil into smell.

So hang it up as soon as you're home, even if it's not going in the wash yet.

Turn it inside out.

The oil is on the side that's been against your skin, so that's the side you want facing the water.

Wash it at the care label temperature.

That's usually 30 or 40 degrees, as high heat can make stretchy fabric lose its stretch.

Use a biological detergent, because the enzymes help make up for the cooler water.

Stick to the dose on the pack, though. Too much leaves residue in the fibres that holds onto smell.

Give it an oxygen bleach soak every few weeks.

Or whenever a top starts to smell straight after a wash.

Soak it for about an hour in warm water with oxygen bleach before it goes in the machine.

A cooler wash can't shift all the built-up oil, and this clears what's left.

Dry it fast.

Hang it somewhere airy, or outside if you can.

Slow, damp drying lets the bacteria wake back up, and that's what brings the smell back.

If you tumble dry it, keep it on low.