Oil your lunchbox before the curry hits it

Coat the container with a thin layer of oil before you add tomato sauce or curry, and for existing stains, baking soda plus dish soap will get most of them out.

The reason this works is simple: the pigments in turmeric and tomato are oil-soluble, and they love latching onto rough plastic and silicone. If you rub a little neutral oil (canola, sunflower, whatever) around the inside and dump out the excess, you create a barrier that the color can’t easily cross. It’s not a magic force field, but it cuts the staining down to near zero.

For stains that already live in there, make a thick paste of baking soda and a squirt of dish soap. Smear it on the stained spots, let it sit for 15–30 minutes, then scrub with a sponge or old toothbrush. That covers most of it. If stubborn yellow turmeric stains remain, put the container out in direct sunlight for a day. Sunlight bleaches those stains better than any chemical cleaner I’ve tried.

Skip the harsh bleach — it can damage the plastic and leave its own smell.

Your lunchbox won’t stay pristine forever, but it’ll survive curry night.