How to get yellow sweat stains out of white shirts

How to remove sweat from white clothes

1. 1

   Check the fiber content

   Read the care label for fiber content and bleach symbols. Note any spandex, nylon, silk or wool, and any colored trim or stitching.

   Why: White fabrics vary. Cotton and polyester take hot water and strong bleach; spandex, nylon, silk and wool can yellow or weaken with chlorine bleach and heat.

2. 2

   Pretreat the underarms

   Rub liquid laundry detergent or a prewash stain remover into both sides of the yellowed area and leave it 5 to 10 minutes.

   Why: Detergent loosens the body oil that holds the yellow layer together, so the soak can reach it.

3. 3

   Soak in oxygen bleach or peroxide

   Dissolve oxygen bleach in the hottest water the shirt can take, as the package directs, or mix equal parts 3% hydrogen peroxide and water. Submerge the armpits for at least 30 minutes, or overnight for old yellowing. An enzyme presoak in the same soak helps if the stains are also stiff or smelly.

   Why: Oxygen bleach releases hydrogen peroxide, which oxidizes the yellow color bodies. It works best in hot water, above about 130°F according to Texas A&M.

4. 4

   Wash hot with plenty of detergent

   Wash in the hottest water the label allows, with a full dose of detergent and more oxygen bleach. Wash whites only, with no colored items.

   Why: Too little detergent or cool water leaves body oil behind, which is what turns whites yellow in the first place. Washing alone stops whites picking up loose dye.

5. 5

   Air-dry, in the sun if possible

   Hang the shirt to dry and check the armpits in daylight. Dry white cotton and linen in sun if you can; dry nylon and silk in shade.

   Why: Dryer heat can bake in remaining yellow. Sunlight helps brighten white cotton and linen but weakens silk and nylon.

6. 6

   Repeat over several washes

   If yellow remains, repeat the pretreatment and soak. Old stains usually fade a little each round.

   Why: Years of build-up don't come out in one soak, and some antiperspirant salts bond with the fabric.

Why white shirts turn yellow under the arms

Sweat carries salts, urea and, from the underarm glands, an oily secretion. Add skin oil, and every wear leaves a little residue in the fabric, especially when shirts are washed cool or with too little detergent. Over time that oil oxidizes and turns yellow. Antiperspirant aluminum salts combine with sweat in the same spot and build up into a stiff, discolored layer.

On white fabric there's nothing to hide it, which is why yellow pit stains show on whites first. The general sweat stain guide covers colored shirts and BO.

Why chlorine bleach isn't the answer

It seems logical to bleach a white shirt with chlorine bleach, but no extension source recommends it for antiperspirant yellowing. Texas A&M warns that chlorine bleach damages spandex, wool and silk and that the yellowing it causes on them can't be reversed. Georgia's extension service adds that it can yellow resin-treated (wrinkle-resistant) cotton and some nylon. Many dress shirts and T-shirts contain one of these.

Oxygen bleach and hydrogen peroxide oxidize the stain without those risks, so they're the first choice. Save chlorine bleach for plain white cotton or polyester labeled bleach-safe, diluted and added to the wash water, never poured on the stain.

By situation

White or chalky marks after washing

Stiff, white residue in the armpit after a wash is antiperspirant build-up, not sweat. Pretreat with a prewash stain remover for 5 to 10 minutes and wash with oxygen bleach. Kentucky and Texas A&M note that heavy aluminum or zinc build-up may be impossible to remove completely.

Yellow armpits that won't fade

Iowa State notes that antiperspirant aluminum compounds can bond with fabric, so some yellowing will only lighten, not disappear. Several overnight soaks are worth trying before giving up on a shirt.

Yellow stains on white pants and collars

Waistbands, collars and cuffs yellow from body oil rather than antiperspirant. Rub in liquid detergent, soak in oxygen bleach in hot water, and wash with a full dose of detergent in the warmest safe water.

Whites yellowing all over

General yellowing often comes from too little detergent, cool washes on oily soil, or hard water. Wash with more detergent and the warmest safe water, and consider a water conditioner. Aging silk, wool, spandex and nylon also yellow on their own.

White silk and wool

No chlorine bleach, no enzyme presoaks, and no hot soaks. Take white silk and wool with underarm discoloration to a dry cleaner.

What not to do

• Don't use chlorine bleach on shirts with spandex, nylon, silk, wool or a wrinkle-resistant finish. It can yellow and weaken these fibers and finishes permanently.
• Don't pour bleach straight onto the armpit. Concentrated bleach spots and weakens fabric. Always dilute it first.
• Don't put a yellowed shirt in the dryer after treatment until the stain is gone. Heat sets remaining oil and protein residue.
• Don't mix vinegar or ammonia with chlorine bleach. Both combinations release toxic gases.

Other methods that work

Salt and lemon juice in the sun

Iowa State's AnswerLine suggests rubbing salt and fresh lemon juice into white T-shirt stains and drying them in the sun. The mild acid and sunlight bleach gently.

Caution: White cotton only. It can weaken or yellow some fibers.

Baking soda paste

Iowa State lists a baking soda and water paste, left on 30 minutes to overnight, for underarm stains. It loosens fatty residue before the wash.

Caution: Rinse it out well before washing.

White vinegar soak

A 10 to 15 minute soak in undiluted white vinegar is another Iowa State option for underarm stains.

Caution: Rinse thoroughly before any bleach, and never combine it with chlorine bleach.

Stain still there?

Chlorine bleach turned the armpits more yellow

The shirt likely contains spandex, nylon or a resin finish, and that yellowing usually can't be reversed. Try an oxygen bleach soak; if nothing changes, the damage is permanent.

The soak didn't seem to do anything

Oxygen bleach needs hot water and time. Use the hottest water the label allows, soak overnight, and pretreat with detergent first.

Safety

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

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

Questions

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