Oxygen bleach: how it works, what it's safe on and how to use it

Step by step

1. 1

   Check the fabric

   Read the care label. Oxygen bleach is fine on most washable cotton, linen and synthetics. Don't use it on wool or silk.

   Why: Dissolved percarbonate is alkaline, and strong alkalis harm protein fibers like wool and silk.

2. 2

   Test the color

   Dissolve 1 teaspoon of oxygen bleach in 1 cup of hot water. Put a few drops on a hidden area, wait 10 minutes, and check. If the color changes, don't use it on that item.

   Why: Oxygen bleach is generally color-safe, but some dyes aren't colorfast.

3. 3

   Dissolve it in hot water

   Wearing gloves, dissolve the amount the product label gives in the hottest water the fabric allows, in a plastic tub or bucket.

   Why: Percarbonate releases its peroxide fastest in hot water; Texas A&M says it works best above 130°F. Metal containers can speed the bleaching enough to damage fibers.

4. 4

   Soak the stained item

   Submerge the item completely and leave it to soak. Give old or stubborn stains a long soak rather than a quick dip.

   Why: Oxygen bleach acts slowly, so it needs time in the solution to break down the stain color.

5. 5

   Wash with detergent

   Launder as usual. To use oxygen bleach in the washer instead, add it to the water with the detergent before the clothes go in.

   Why: Texas A&M advises adding it to the water with the detergent before the clothes, so the powder is dissolved before it reaches the fabric.

6. 6

   Check before drying

   Look at the stain after washing. If a trace is left, soak again before using the dryer.

   Why: Dryer heat can set what remains.

What oxygen bleach is and how it works

The powdered oxygen bleach in US stores is mainly sodium percarbonate: washing soda (sodium carbonate) bound to hydrogen peroxide. In water it splits back into the two. The peroxide oxidizes the colored residues stains leave behind, breaking them down so they fade. The sodium carbonate raises the pH, which helps loosen and lift soil.

Older products used sodium perborate instead. Liquid "color-safe" bleaches are usually dilute hydrogen peroxide, so they're a weaker version of the same chemistry.

Compared with chlorine bleach, oxygen bleach is slower and gentler. That's why it's safe for most washable colored fabrics, and also why it needs hot water or a long soak to do its job. Used briefly in cold water, it does little.

What oxygen bleach is good for, and what it harms

Good for:

• Dye and tannin residues on colored fabric that can't take chlorine bleach: traces of coffee, tea, wine, fruit, grass and mustard. Kentucky's extension guide says to soak in oxygen bleach, then launder.
• Mildew and scorch on fabrics that aren't safe for chlorine: soak in oxygen bleach and hot water, then launder.
• Heavy deodorant buildup and stubborn sweat stains: pretreat, then launder with oxygen bleach.
• Whitening and brightening. It acts as a whitener on whites and a brightener on colors.

Harms or needs caution:

• Dyes that aren't colorfast. Run the 10-minute test first.
• Wool and silk. Extension guidance warns that strong alkalis harm them. An older Michigan State bulletin says perborate bleach "sometimes may be used" on wool and silk; follow the care label, and when in doubt, don't.
• Metal. Don't mix, soak or store it in metal containers. Metal can speed the bleaching enough to damage fibers and may tarnish and stain fabric.

Temperature, dose, and what never to mix

• Water temperature: hot is best. Texas A&M puts it above 130°F. In cooler water, expect to soak longer.
• Dose: follow the product label, because concentrations differ between products.
• Dye transfer in the wash: Texas A&M suggests rewashing with 1 cup of non-chlorine bleach plus detergent.
• Color test: 1 teaspoon in 1 cup of hot water, a few drops on a hidden area for 10 minutes.

Never combine it with chlorine bleach. Chlorine bleach stops oxygen bleach's bleaching action, so you lose the benefit of both. Use one or the other.

Don't combine it with vinegar or other acids in a closed container. Dissolved oxygen bleach releases hydrogen peroxide, and peroxide plus vinegar forms peracetic acid, which is corrosive. See never mix these cleaners.

By situation

Coffee, tea or wine on a colored shirt

After rinsing and pretreating, soak the shirt in oxygen bleach dissolved in the hottest water the label allows, then wash. Test the color first.

Dye ran onto other clothes in the wash

Don't dry them. Rewash with about 1 cup of non-chlorine bleach and detergent, as Texas A&M suggests, and repeat if the color is still fading.

Dingy whites

Oxygen bleach works as a whitener in a hot wash or soak, and it's an option for whites whose care label rules out chlorine bleach.

Cold-water-only fabrics

Oxygen bleach still works in cooler water, but more slowly. Make up for it with a longer soak rather than more powder than the label allows.

Wool and silk

Skip it. The alkaline solution harms protein fibers. Use a method suited to the fabric, or take the item to a professional cleaner.

What not to do

• Don't use oxygen bleach on wool or silk. Dissolved percarbonate is alkaline, and strong alkalis damage protein fibers.
• Don't mix it with chlorine bleach. Chlorine bleach stops the bleaching action of oxygen bleach, so you lose the benefit of both.
• Don't soak in a metal container. Metal speeds the bleaching enough to damage fibers and can tarnish and leave stains.
• Don't store dissolved oxygen bleach in a closed bottle. Wet percarbonate keeps releasing oxygen, so mix it fresh each time.
• Don't expect fast results in cold water. It's a slow bleach that works best hot or with a long soak.

Other methods that work

3% hydrogen peroxide

The same active ingredient, applied as a liquid to a single spot. Handy for a small mark on a white shirt when you don't want to soak the whole garment.

Caution: It can lighten dyes. Test first.

Chlorine bleach

Faster and stronger, for fabrics whose care label allows chlorine bleach.

Caution: Never use it together with oxygen bleach, and never mix it with ammonia, acids or alcohol.

Stain still there?

The stain didn't change after a soak

Use hotter water if the fabric allows, or soak longer. If the stain is protein or grease rather than color, oxygen bleach isn't the right tool: treat it with an enzyme detergent or a degreasing pretreatment first.

A color test spot changed

That dye isn't stable in oxygen bleach. Don't use it on that garment.

Whites still look dull

Check the dose on the label and the water temperature. Oxygen bleach in a cool, short cycle does very little.

Safety

• Sodium percarbonate can cause serious eye damage and is harmful if swallowed. Wear gloves and avoid breathing the dust.
• Keep the powder dry, in its original container and out of reach of children. It's an oxidizer and can intensify a fire.

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

Questions

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