Question

Can I put a pizza box in the oven to keep it warm?

Answer 1

Yes you can preheat the oven to 200 F and then turn the oven off but place the Pizza with the cardboard box inside the oven for awhile and the heat from the oven will keep the pizza warm enough in the cardboard box.

However if you leave the oven on it may eventually catch the cardboard box on fire or at least burn it somewhat should you forget to turn the oven off.

So yes you can put the cardboard box and pizza in the oven on 200 F for a little while but after around 30 minutes or so turn the oven off and let the heat in the oven itself keep the pizza warm.

Answer 2

You can put a cardboard pizza box in the oven to keep it warm on a low setting but I prefer to just remove the pizza from the pizza box and place it on a pizza pan or even just some aluminum foil to heat it.

If I remove it from the pizza box I can leave the pizza in the oven longer without worry of catching the pizza box on fire but as long as you watch the oven closely and don't leave the cardboard pizza box in the oven too long then it should be okay.