Sunlight Actually Works on Tomato Stains

Sunlight actually works for tomato sauce stains on plastic — it’s one of those old kitchen tricks that holds up.

Here’s why the stain is so stubborn in the first place: tomatoes contain lycopene, an oil-soluble pigment that seeps into the microscopic pores of the plastic. Regular dish soap and scrubbing only clean the surface — the red is living inside the material, not on top of it.

The sunlight fix is real photochemistry. UV light literally breaks down the lycopene molecules, so the color fades away. Wash the container with cold soapy water first (hot water sets the stain deeper), then leave it in direct sunlight for a few hours. Outside is best — window glass filters out some of the UV that does the work. Flip it once or twice so all sides get hit, and the stain should be mostly gone by the end of the day.

A few things that help alongside sunlight: a paste of baking soda and water lifts stubborn bits, and a diluted bleach soak works but can cloud some plastics. To prevent it in the first place, rub a thin coat of oil around the container before adding sauce — it fills the pores the pigment would otherwise sink into.

Or just accept the pink tint and call it character.