The freezer door is the worst place for ice packs

Warm soapy water and a full air-dry will clean the lunch box, and the ice packs perform best when frozen flat in the coldest part of the freezer — not the door.

For cleaning, pull the ice packs out first. Hand wash the lunch box with dish soap and warm water, inside and out. Most insulated lunch boxes shouldn’t go in the dishwasher — the heat can warp the lining and wreck the insulation. For stuck-on smells, a baking soda paste does the job. Then air dry it completely with the lid open. Trapped moisture is what turns a lunch box funky, so don’t rush this step.

For the ice packs themselves, wipe them down with soapy water. Don’t submerge them. Even a small seam or valve can let water in, which dilutes the coolant and can grow mold inside the pack where you can’t see it.

For maximum cooling, freeze the packs flat and spread them out so cold air can circulate around each one. Stacking them while they’re still liquid traps heat in the middle and slows freezing. Once they’re solid, stack away. And keep them on the back or bottom shelf of the freezer — the door thaws and refreezes every time someone opens it, so packs stored there are never as cold.

One more thing: put the frozen packs on top of your food, not underneath. Cold air sinks, so it settles down over everything. You’ll keep the lunch noticeably colder.

A dry box and a rock-solid pack are the difference between a good lunch and a warm one.