Baking soda beats vinegar for old lunchbox stains.

Baking soda is the better choice for old curry and tomato stains on plastic, and it’s not close. Vinegar mostly just smells like it’s working.

Here’s the thing: vinegar is an acid. Acids are fine for hard water spots and glass, but they don’t do much to the oily, pigmented mess that curry and tomato leave behind. Curry stains are basically turmeric suspended in oil, and tomato is an acid-based dye. Vinegar isn’t cutting through either of those, and it has zero scrubbing power. You’re just wetting the stain and calling it a day.

Baking soda wins because it works two ways at once. It’s a mild abrasive, so it physically scrubs the stain out of the plastic’s pores, and it’s alkaline, which helps break down the gunk and absorb odors. Even better: don’t make it a contest. Hit the container with hot water and dish soap first to cut the oils, then make a thick baking soda paste and let it sit for 15–20 minutes before scrubbing with a sponge or soft brush. Rinse, and the smell goes with it.

One more trick that beats both: sunlight. If it’s a tomato or turmeric stain, set the clean container in direct sun for a few hours. UV light actually breaks down those pigments. It sounds like a grandma hack, but it works on old plastic.

Skip the bleach, by the way. It can damage the plastic and leave its own residue you don’t want near food.

Vinegar has its place. Old lunchbox stains just aren’t it.