Sunlight is the secret to stained lunch boxes

Baking soda paste handles most plastic lunch box stains, but sunlight is the real trick for stubborn tomato and curry marks.

First, degrease. Tomato and curry stains are oil-based pigments, so dish soap is step one. If you skip it, you’re just scrubbing at grease.

Then make a paste of baking soda and a little water, rub it into the stain, and let it sit for 15 minutes. Rinse. That gets 80% of stains.

The stubborn 20% — especially turmeric — needs UV light. Wash the box, leave it slightly wet, and set it in direct sun for a few hours. Sunlight breaks down the pigment molecules. Sounds like a Pinterest hack, but it genuinely works on plastic.

Don’t go at it with steel wool or a hard brush. Scratches just give the next stain more places to hide. And skip the bleach soak unless you want your lunch to smell like a pool.

If it’s still stained after sun and baking soda, that stain is part of the plastic now. Bin it and buy a new one. Lunch boxes aren’t heirlooms.