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Protocol
Method steps
- Read the bleach triangle A crossed-out triangle means bleaching is not allowed; an empty triangle or one with two oblique lines allows oxygen bleach (GINETEX).
- Keep it off wool and silk Vanish says its percarbonate powder should not be used on delicate items like silk or wool (Vanish).
- Test coloured items on a hidden area Test for colourfastness in an inconspicuous area before use (OxiClean).
- Dissolve the powder before the fabric goes in Add the powder to the water before the fabric, and do not mix it with chlorine bleach (OxiClean).
- Soak for the time on the pack, then wash Follow your product's soak time (OxiClean's is 1 to 6 hours), then wash as normal (OxiClean).
- Never seal a mixed solution Keep it in an open or loosely closed container: it keeps giving off oxygen, and a sealed container can build pressure and rupture (OxiClean).
The care label’s bleach triangle decides first whether a garment can take sodium percarbonate: a crossed-out triangle means no bleaching at all. Two sellers of the powder say not to use it on wool or silk. After that, the dose and soak time are the ones on your product’s pack, and a mixed solution should never be sealed.
Sodium percarbonate is an addition compound of hydrogen peroxide and sodium carbonate; by weight, the pure substance contains 32.5% hydrogen peroxide and 67.5% sodium carbonate. It dissolves rapidly in water and dissociates into sodium ions, carbonate ions and hydrogen peroxide, and a 1% solution has a pH of about 10.5 at 20 °C (OECD (external link)). For baking soda, see baking soda in laundry.
What each garment allows, task by task
Find your garment in the first column, then read across to the job you want to do. The label gate comes first; the product’s own fabric limits and directions still apply after it. If the triangle on your label is crossed out, then stop at the third row: bleaching is not allowed (GINETEX (external link)).
| Garment | Whitening soak | Stain soak or paste | Odour (in the wash) | Gate and source |
|---|---|---|---|---|
| White, triangle empty or with two oblique lines | Yes, if the product's directions cover the fabric | Yes, if the product's directions cover the fabric | Yes, if the product's directions cover the fabric | Triangle allows oxygen bleach (GINETEX); product limits, e.g. Vanish presents Crystal White for white cotton or polyester (Vanish) |
| Coloured, triangle empty or with two oblique lines | Not applicable | Only with a product whose directions cover the fabric, after its colourfastness test | Only with a product whose directions cover the fabric, after its colourfastness test | GINETEX; OxiClean's directions include a colourfastness test in an inconspicuous area (OxiClean) |
| Any garment, crossed-out triangle | No | No | No | Bleaching not allowed (GINETEX) |
| Wool | No | No | No | Vanish; percarbonate supplier |
| Silk | No | No | No | Vanish; percarbonate supplier |
| Rust or hard-water marks, any fabric | Not applicable | Not removed, per the supplier | Not applicable | Percarbonate supplier |
The odour column rests on the makers’ own descriptions. Vanish describes the sodium percarbonate in its Oxi Action Crystal White powder as releasing active oxygen to lift out stains and odours (Vanish (external link)). A percarbonate supplier’s use sheet says that in the laundry sodium percarbonate is used to destain, deodorize and whiten (The Chemistry Store (external link)).
The last row comes from the same sheet: the supplier says sodium percarbonate will not remove rust stains or mineral deposits from hard water (The Chemistry Store (external link)).
For which fibres take chlorine and which take oxygen bleach, the fibre-by-fibre chart is in what fabrics can you bleach.
It may already be in your detergent
Sodium percarbonate is mainly used as a bleaching chemical in laundry detergents (tablets, compact or regular powders), laundry additives and machine dishwashing products, and the pure product is sold to consumers as a laundry additive (OECD (external link)). GINETEX notes that oxygen bleach is contained in universal detergents (GINETEX (external link)).
What three products’ directions say
Each row below is one product’s own directions, with the use it names. Doses and times are not transferred between rows.
| Product | In the wash | Soak | Paste | Temperature | Source |
|---|---|---|---|---|---|
| Pure sodium percarbonate (supplier sheet) | With detergent, per load: 1 oz (about 28 g) for light soils, 2 oz (about 57 g) moderate, 4 oz (about 113 g) heavily soiled | For whitening old linens or yellow armpit stains: 2 oz per US gallon (about 15 g per litre), at least 1 hour or overnight, then rinse | Not given for laundry | Most effective warm to hot, 100 to 150 °F (about 38 to 66 °C); solution active 5 to 6 hours, then discard | The Chemistry Store |
| OxiClean Versatile (a blend that contains sodium percarbonate) | Powder and detergent in the drum before the laundry, then wash as normal | Scoop to line 2 to 4 per gallon, 1 to 6 hours (some stains may need longer), then wash as normal | Not given | Any temperature, best warm to hot; not boiling | OxiClean |
| Vanish Oxi Action Crystal White | After the pre-treat, another scoop in the wash with regular detergent | Not given on the product page | 1/4 scoop powder with 3/4 scoop water, rubbed on the stain, 5 minutes maximum | Not given | Vanish |
The first row is for pure sodium percarbonate↗; the second is for OxiClean Versatile Stain Remover↗. The full whitening routine for yellowed whites is in how to whiten yellowed whites.
Item-specific soaks on the supplier sheet
The same supplier sheet gives directions for particular items. To whiten and deodorize diapers, it adds 4 to 6 oz (about 113 to 170 g) of sodium percarbonate to the soak cycle, soaks in hot water for at least 30 minutes, or overnight, then completes the wash cycle. For curtains and sheers that are yellow, dingy or smoke-stained, it soaks them for 30 to 60 minutes in a solution of 2 to 8 oz per US gallon of hot water (about 15 to 60 g per litre), then rinses them thoroughly with fresh water and lets them dry (The Chemistry Store (external link)). Both still go through the triangle check in step 1 below.
What the sources say about water temperature
OxiClean says its Versatile Stain Remover works in any temperature water, but best in warm to hot water, and not in boiling water (OxiClean (external link)). The supplier says percarbonate solutions are most effective when mixed and used in warm to hot solutions (100 to 150 °F, about 38 to 66 °C) (The Chemistry Store (external link)). Choosing the wash setting itself is covered in the laundry temperature guide.
How to use it, step by step
1. Read the bleach triangle
Empty triangle — chlorine and oxygen bleach allowed 
Two oblique lines — oxygen bleach only, no chlorine 
Crossed-out triangle — bleaching not allowed On the care label, an empty triangle allows chlorine and oxygen bleach, a triangle with two oblique lines allows oxygen bleach but not chlorine bleach, and a triangle with a diagonal cross means bleaching is not allowed. The number in the wash tub is the maximum washing temperature in degrees Celsius, which must not be exceeded, whatever the pack says (GINETEX (external link)).
Not sure which triangle you have?The decoder reads the whole care label, including the wash-tub number that caps how hot a soak can be.
Decode the label2. Keep it off wool and silk
Vanish says its Oxi Action Crystal White powder should not be used on delicate items like silk or wool (Vanish (external link)). The percarbonate supplier also says sodium percarbonate is not suitable for use with silk or wool (The Chemistry Store (external link)).
3. Test coloured items on a hidden area
OxiClean says to test for colourfastness in an inconspicuous area before use (OxiClean (external link)). For a garment that has already picked up another item’s dye, see colour bleeding in laundry.
4. Dissolve the powder before the fabric goes in
OxiClean says to add the powder to the water before the fabric, and not to mix it with chlorine bleach, or with household chemicals other than regular laundry detergent in the wash (OxiClean (external link)).
5. Soak for the time on the pack, then wash
Use the soak time your product gives in the table above (OxiClean’s is 1 to 6 hours), then wash as normal (OxiClean (external link)).
6. Never seal a mixed solution
OxiClean says to keep a mixed solution in an open or loosely closed container: it keeps giving off oxygen, and in a sealed container pressure can build until the container ruptures and causes injury (OxiClean (external link)).
Storing and handling the powder
In the hazard classifications companies have notified to the EU chemicals agency, as aggregated by PubChem, sodium percarbonate is most often labelled “harmful if swallowed” (97.4% of 1,138 company reports) and “causes serious eye damage” (94.6%), and in 46.1% of the reports “may intensify fire; oxidizer” (PubChem (external link)). In animal tests, solid sodium percarbonate was slightly irritating to the skin and highly irritating to the rabbit eye when not rinsed (OECD (external link)). The OxiClean Versatile safety data sheet classifies that product as causing serious eye damage and advises protective gloves, protective clothing and eye protection (Church & Dwight (external link)).
If powder gets in your eyes
Solvay’s first aid for eye contact: flush with running water for 15 minutes, keeping the eyelids wide open, and consult an ophthalmologist in all cases (Solvay (external link)).
Solvay, which makes sodium percarbonate, gives this storage advice for its packaged product. It says sodium percarbonate naturally decomposes very slowly into sodium carbonate, water, oxygen and heat, and that when handled properly it can be stored for several months without a significant loss of available oxygen. It lists water, transition metals, organic materials, acids, bases, reducing agents and dirt as contaminants that can start or speed up decomposition, and says to store the powder away from any heat source. It is non-flammable, but when it decomposes it can support combustion by releasing oxygen and heat, so it should be kept away from combustible materials such as paper, rags and wood. Keep it in a dry, clean place, protected from heat, direct sunlight and moisture (Solvay (external link)).
Related reading
- What fabrics can you bleach?: the fibre-by-fibre chlorine and oxygen chart.
- How to whiten yellowed whites: the whitening routine for dingy whites.
- Colour bleeding in laundry: rescuing a load after dye transfer.
- Laundry temperature guide: choosing the wash temperature.