Stainless Steel Lunch Box Care Instructions

Your stainless steel lunch box needs three things. A rinse before the first meal. A dry seal groove. A closed latch before it goes in the bag. Everything else is on this page.

Sizes	27 oz, 40 oz, 47 oz
Material	18/8 stainless steel, uncoated inside. Silicone seal. No plastic.
Dishwasher	Box, lid and seal all go in. No temperature limit.
Insulation	None. This box is not insulated and holds no temperature rating.
In the box	2 dividers, a spare seal, a 100% cotton bag
Tested	Independently tested for lead under the US CPSIA. Report dated July 22, 2026.

Before the first use

Wash it once with warm water, with the seal taken out.

1. Take the seal out of the lid. Pull the silicone seal out of its groove. It comes out with your fingers, no tool needed.
2. Wash both parts with warm water. Box, lid and seal. Dish soap is fine, and so is the dishwasher.
3. Dry the lid and the groove. Dry the lid and the groove the seal sits in. A dry groove is what makes the seal hold.
4. Press the seal back in. Work your way around the groove so it sits flat everywhere. Then close the latches once to check.

Cleaning it in the dishwasher

Box, lid and seal all go in the dishwasher. There is no temperature limit.

1. Take the seal out once a week. It can stay in for a normal wash. Taking it out weekly lets the groove dry fully.
2. Load the box open, face down. Water needs to reach the corners. A box lying closed comes out with a puddle in it.
3. Dry the seal groove afterwards. Dry the lid and the groove the seal sits in. A dry groove is what makes the seal hold.

Sterilizing it in boiling water

Five minutes in boiling water, with the seal taken out first.

1. Take the seal out of the lid. Boil it along with the box, loose, not seated in the groove.
2. Boil for 3 to 5 minutes. Box, lid and seal together. Longer does not help.
3. Lift everything out and dry it. Dry the lid and the groove the seal sits in. A dry groove is what makes the seal hold.

Before you pack it

Check two things: both latches closed, and the seal sitting flat.

1. Run a finger around the seal. It should sit flat in the groove the whole way round. A lifted corner is where leaks start.
2. Close both latches until they snap. You hear it. If you do not hear it, the lid is not down.
3. Let hot food cool first. Food packed steaming pulls a vacuum as it cools, and the lid then fights you at lunch.

Using the two dividers

Two dividers turn one compartment into two or three.

1. One divider makes two compartments. Slide it in where you want the wall. Greens on one side, protein on the other.
2. Two dividers make three. Main, side, and something small. A boiled egg fits, which surprises people.
3. Clip the two dividers together for a tighter fit. Joined, they wedge against the walls and nothing shifts on a bumpy commute.

Washing the cotton bag

Hand wash only, in warm water at around 86 °F.

1. Hand wash in warm water. Around 86 °F. Hotter water shrinks the cotton.
2. Air dry it. No dryer. The bag keeps its shape and its print that way.

When something wears out

A worn seal means you buy a seal, not a new box. Every wearing part on this box is sold on its own.

• Seal set
• Dividers
• Replacement lid
• Locking bar set
• All spare parts

Questions we get asked

Is the stainless steel lunch box dishwasher safe?

Yes. The box, the lid and the seal all go in the dishwasher, at any temperature your machine runs. Take the seal out once a week so the groove underneath dries fully.

Why is my lid hard to open?

The food went in hot. As it cools it pulls a vacuum, and the vacuum holds the lid down. Let food cool before you close the box. If it is already stuck, open one latch and wait a moment.

Can I put the lunch box in the oven?

The steel box can go in the oven. The seal and the latches cannot. Take the lid off completely first, and never put the lid, the seal or the dividers in the oven.

Does it leak?

It is built to be leak-proof for everyday food, sealed on its side in a backpack. Thick food such as yogurt, curry or dressing stays where it belongs. Clear soup is better carried upright.

How do I get rid of a smell?

Steel is non-porous, so smells do not soak in. If something lingers it is almost always the silicone seal. Take the seal out, boil it for three minutes, dry it, and press it back in.

Is it safe for a child's lunch?

The lunch box is independently tested for lead under the US CPSIA. The report is dated July 22, 2026. You can download it on our certificates page, with no form and no account.