How to Treat White T-Shirts for Stains (Including Yellow Pit Marks)

White t-shirts are a wardrobe essential — until they start to show stains. Whether it’s a splash of coffee, a mystery smudge, or the dreaded yellow underarm discoloration, here’s how to treat them so they stay crisp and wearable.

Step 1: Pre-Treat the Underarms

Yellowing underarms aren’t just sweat — it’s sweat plus deodorant buildup. To lift them:

  • Mix a paste of baking soda + hydrogen peroxide + mild detergent
    (Ratio: 1:1:1 — about 1 tbsp of each for one shirt)

  • Apply the paste to the stained area and gently scrub with a soft brush

  • Let sit for 30 minutes before washing

For stubborn marks, you can soak the shirt in warm water with oxygen bleach (like OxiClean) overnight.

Step 2: Spot-Treat Other Stains

  • Oily stains: Apply a few drops of dish soap directly to the spot and gently rub in

  • Makeup marks: Use micellar water or a dab of shaving cream before laundering

  • Food splatters (ketchup, wine): Rinse immediately in cold water, then use a stain remover spray before washing

Step 3: Wash in Cold with the Right Detergent

Use a detergent that’s made for whites but doesn’t contain optical brighteners (which can dull over time). I like Dirty Labs because it’s effective without being harsh.

Wash in cold water to prevent setting any missed stains.

Step 4: Air Dry + Inspect

Avoid tossing it in the dryer until you know the stain is gone — heat can permanently set it.

Hang dry or lay flat in the sun if possible (sunlight acts as a natural brightener).

Bonus Tip: Prevent Future Pit Stains

  • Switch to an aluminum-free deodorant

  • Let deodorant dry fully before dressing

  • Wash white shirts as soon as you can — don't let sweat sit

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