Plastic and glass boxes on Passover

Hello, Your Honor,
I would be happy if you could help me with a question that has arisen regarding kosher during Passover.
My partner’s house keeps kosher during Passover, but I noticed that they use plastic and glass boxes to preserve food (which are used every day, including for leaven).
And I’m not sure they did anything to train them.
Is it normal because the food in the boxes is cold?