Most plastic food containers are made for the dishwasher, but the top rack is the safe place. The bottom rack is nearer the heating element and warps them.
Tupperware and similar plastic containers are usually labelled dishwasher safe, with the top rack as the rule. The heating element sits at the bottom, and thin plastic placed near it warps. Older containers, thin takeout tubs and anything without a symbol are less certain.
| Short answer | Usually yes, on the top rack |
|---|---|
| Where | Top rack, away from the heating element |
| Check | The dishwasher safe symbol or the maker guidance |
| Not suitable | Takeout tubs and thin single use containers |
| Stains | Tomato and curry stain plastic regardless |
How to wash plastic containers in the dishwasher
- Look for the dishwasher safe symbol or the maker guidance on the base.
- Put the container and its lid on the top rack, open side down.
- Keep them clear of the heating element and the drying vent.
- Skip the heated dry setting if you can, because it is where warping happens.
- Let them cool before sealing, so the lid fits properly afterwards.
What happens when you get it wrong
- Warped lids. The lid no longer seals, which is the whole job of the container.
- Melted spots. Plastic near the element can soften and deform.
- Cloudy plastic. Repeated hot cycles dull the surface over time.
Hand washing for old or thin containers.
Glass containers for tomato sauces and curries, which do not stain.
Frequently asked questions
Is all Tupperware dishwasher safe?
Many modern pieces are, but not all. Look for the dishwasher safe symbol on the base, and hand wash anything that does not carry it, including older pieces.
Why do plastic lids warp in the dishwasher?
Heat from the element and the drying cycle softens plastic. The top rack and air drying reduce it.
Can you put takeout containers in the dishwasher?
Usually no. They are made for single use and are thin.
Can you remove stains from plastic containers?
A soak in warm water with baking soda can help, but tomato stains often fade slowly in sunlight.