Updated

Updated · The Guardian · Nov 10

Author Tests 10 Science-Backed Laundry Fixes, Solving Oil Stains but Struggling With Sunscreen

Updated

Updated · The Guardian · Nov 10

Author Tests 10 Science-Backed Laundry Fixes, Solving Oil Stains but Struggling With Sunscreen

Q: Could the sunscreen protecting your skin be reacting with iron in your wash water to permanently ruin your clothes?

Yes. A common sunscreen ingredient, avobenzone, can react with iron in wash water and create yellow, orange or rust-colored marks on clothing, especially white or light fabrics. The article and supporting material both point to this as a real laundry problem, not a myth. That does not mean the damage is always permanent, but it can become much harder to remove if the garment is repeatedly washed, dried with heat, or treated with chlorine bleach. Ordinary detergent often will not fix this kind of stain because it is not just oil; it is also a metal-related discoloration. Rust- or iron-stain removers are usually more effective, though repeated treatment may be needed and some marks can return after drying. The key clue is timing. If the stain appears as a greasy patch right after sunscreen touches the fabric, it is likely the oily base and should be pretreated with detergent. If it shows up or deepens after washing, especially as yellow or orange patches, that suggests a reaction between avobenzone and iron or minerals in the water. Mineral sunscreens, by contrast, are more likely to leave chalky white residue. To reduce the risk, let sunscreen dry before dressing, wash stained items promptly, avoid heat until the mark is gone, and skip chlorine bleach, which can set the discoloration. In hard-water areas, treating the water or using products designed to remove iron can help protect clothes.

3 articles · Updated · The Guardian · Nov 10

Ten home laundry tests found science-led methods worked best on several stubborn problems, with lipase detergent and bicarbonate clearing cooking oil, WD-40 lifting black chain grease, and UV sunlight bleaching tomato stains.
Sunscreen proved the toughest case: rust remover erased yellowing caused by avobenzone-metal oxidation, but the stain returned after drying because the metal ions remained in the fabric.
Other trials delivered mixed gains — citric acid and repeated washes softened deodorant-crusted armpits, citric acid rinse and water softener improved crunchy towels, and a DNAse booster cut heat-reactivated gym-clothes odor.
Two failures underscored the limits of laundry chemistry: oxygen remover slightly bleached a colored shirt, and a polyquat dye-transfer stain resisted reductive bleach, likely because indigo dye was involved.
The experiments drew on advice from r/laundry moderator Eric Thompson and polymer chemist Clare Mahon, reflecting a broader push to use chemistry to extend clothing life while avoiding unsafe product mixing.