Sunlight beats any cleaner for plastic stains.

Sunlight beats every natural cleaner for tomato and turmeric stains on plastic lunch boxes.

The trick is embarrassingly simple: put the stained container in direct sunlight for a few hours. Those stains are pigments, not dirt — turmeric has curcumin, tomato has lycopene — and UV light breaks the pigment molecules down. The stain will fade dramatically, and often vanish completely by the end of the day.

If you’re in a hurry, a thick paste of baking soda and a little water works too. Rub it gently with a soft sponge, then rinse. Just don’t scrub hard — scratched plastic holds onto stains even worse next time. A warm vinegar soak for 20 minutes before scrubbing helps loosen things up.

One thing I’d skip: citrus juice and salt, which people recommend but it’s messy and doesn’t work any better than the baking soda. And never use a scouring pad on a container you plan to see again.

Let the sun do the scrubbing.