How to remove sweat stains from shirts

How to remove sweat from clothes

1. 1

   Check the label and the fabric

   Read the care label for the hottest safe water temperature and any bleach warnings. Silk and wool shirts get a gentler treatment (see the situations below).

   Why: Enzymes and oxygen-bleach boosters can damage protein fibers, and the water temperature you can use decides how much the wash can lift.

2. 2

   Pretreat the underarms

   Turn the shirt inside out. Rub liquid laundry detergent or a prewash stain remover into the stained area on both sides, or work in bar soap, and leave it for 5 to 10 minutes. Don't let it dry on the fabric.

   Why: Detergent surfactants loosen the body oils that hold the stain together, which lets the soak reach the protein underneath.

3. 3

   Soak in an enzyme presoak or oxygen bleach

   Mix an enzyme presoak or oxygen bleach with warm water as the package directs and submerge the shirt. Give fresh stains 30 minutes and old, yellowed pit stains several hours or overnight.

   Why: Protease enzymes cut sweat proteins into pieces that rinse away, and oxygen bleach oxidizes the yellow discoloration. Iowa State's guide lists soaks from 30 minutes to overnight.

4. 4

   Wash in the hottest water the label allows

   Wash the shirt as usual, in the warmest water that's safe for the fabric, with a full dose of detergent. Add oxygen bleach to the wash for stubborn stains.

   Why: Once the residue is loosened, heat helps the detergent carry away body oil that cool washes tend to leave behind.

5. 5

   Air-dry and check

   Hang the shirt to dry and look at the underarms in daylight. If a shadow remains, repeat the pretreatment and soak before it goes near the dryer or an iron.

   Why: Dryer and iron heat set leftover protein and oil, and can bake in the yellowing.

6. 6

   Restore changed color if needed

   If the fabric color itself looks changed rather than stained, test on a seam first, then dab household ammonia on a fresh stain or white vinegar on an old one. Rinse well and rewash.

   Why: Sweat can shift some dyes. Fresh sweat tends to be acidic and old stains alkaline, so the opposite pH can sometimes bring the color back.

What pit stains actually are

Sweat on its own is mostly water with salts, lactic acid and urea, plus an oily secretion from the underarm glands. That's a protein stain with oil mixed in. Washing in cool water every week leaves a little body oil behind each time, and it builds up in the fabric around the armpits and collar.

Antiperspirant adds a third layer. Its aluminum salts combine with sweat and collect in the fibers, and Iowa State notes that these compounds can bond with the fabric, so heavy build-up may never come out completely. That's why one wash rarely fixes an old pit stain and why repeated soaks over several washes do better.

Why a soak works better than scrubbing

Scrubbing moves the surface residue around but doesn't break it down. An enzyme cleaner digests the protein part, and oxygen bleach releases hydrogen peroxide in water, which oxidizes the yellow color. Both need time in contact with the fabric, which is what the soak provides. Hard rubbing also roughens the fabric, and worn underarm fabric holds new stains more easily.

By situation

Old pit stains that survived washing and drying

These are set. Soak in oxygen bleach or an enzyme presoak overnight and wash in the hottest safe water, then repeat over several wash cycles. Some fade a little each time; heavy antiperspirant build-up may only lighten.

Stiff or white marks after washing

A stiff, chalky patch in the armpit after washing is usually antiperspirant build-up rather than sweat. Pretreat with a prewash remover for 5 to 10 minutes and wash with oxygen bleach. Kentucky and Texas A&M note that heavy build-up of aluminum or zinc salts may be impossible to remove. The deodorant stain guide covers this in more detail.

Colored and dark shirts

Use oxygen bleach rather than chlorine bleach, and test ammonia, vinegar and hydrogen peroxide on an inside seam first, since all three can change dyes. If the armpit looks faded or discolored rather than yellow, the sweat has changed the dye: that's when the ammonia or vinegar step applies.

White shirts with yellow armpits

Whites can take stronger oxidizing soaks, such as equal parts 3% hydrogen peroxide and water. The white shirt guide covers yellowing in detail.

Silk, wool and dry-clean-only shirts

Skip enzyme presoaks, which digest protein fibers, and chlorine bleach. If you use ammonia on wool or silk, dilute it with an equal amount of water and test first. Suits, dresses and anything labeled dry clean only should go to a cleaner, with the stain pointed out.

BO smell that stays after washing

The smell lives in the same body oil and protein residue as the stain. Kentucky's guide says most odors come out in one or more washes with a detergent formulated for odors, and stubborn perspiration responds to an enzyme product or oxygen bleach in the hottest water safe for the fabric. See the sweat smell guide for gym clothes and synthetics.

What not to do

• Don't machine-dry or iron a shirt with a visible pit stain. Heat sets the protein and oil residue, which makes the yellowing much harder to remove.
• Don't reach for chlorine bleach for yellow armpits. No extension source recommends it for antiperspirant yellowing, and it damages silk, wool and the spandex found in many shirts.
• Don't mix ammonia or vinegar with chlorine bleach. Ammonia plus bleach releases chloramine gas, and vinegar plus bleach releases chlorine gas. Rinse well between treatments.
• Don't scrub the armpits hard. It roughens the fabric without breaking down the residue, and abraded fabric picks up stains faster.

Other methods that work

White vinegar soak

Iowa State lists a 10 to 15 minute soak in undiluted white vinegar for underarm stains before washing. Vinegar's acid can also restore dye changed by old, alkaline sweat.

Caution: Test on colored fabric, rinse before any bleach, and never combine it with chlorine bleach.

Baking soda paste

A paste of baking soda and water spread on the underarms and left 30 minutes to overnight is also listed by Iowa State. As a mild alkali it helps loosen fatty residue.

Caution: Rinse it out well before washing.

3% hydrogen peroxide

Equal parts 3% hydrogen peroxide and water makes a soak that oxidizes yellowing. It's most useful on whites and light colors.

Caution: It can lighten dyes, so test on a seam first. Use only the 3% drugstore strength.

Stain still there?

The stain faded but a yellow ring is still there

That's usually the oxidized oil and antiperspirant layer. Repeat the oxygen bleach soak overnight and wash hot; it can take several rounds.

The fabric feels stiff and won't soften

Aluminum salts have built up and may be bonded to the fibers. Pretreat with a prewash remover and wash with oxygen bleach a few times. If nothing changes, the build-up is probably permanent.

The armpits smell again as soon as you sweat

Residue is still in the fabric. Soak with an enzyme presoak, wash in the hottest safe water, and air-dry in the sun if you can.

Safety

• Never mix ammonia or vinegar with chlorine bleach.
• Use only 3% hydrogen peroxide, not hair-bleaching strength.
• Ventilate when working with household ammonia.

Never mix cleaning products; see chemicals you must never combine.

Questions

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