How can I remove metallic odor from a new insulated casserole carrier?

put a open box of baking soda in it.

You can also try: Mix 2 cups of white distilled vinegar with 2 cups of lukewarm water in a large bowl. Add in 4 heaping tablespoons of baking soda, adding it in smaller amounts if it threatens to fizz over (and it really does fizz!) Pour into a spray bottle and thoroughly spray the area

A charcoal briquette placed in the carrier should absorb the odor.

thank you for your comments. My daughter says the odor will go away......

A friend closed up her cottage for the winter and forgot to take some fruit out and leave the fridge door open. In the spring, the fruit was all moldy and there was a terrible odor in the fridge. She was ready to buy a new one but I talked her into filling it with newspaper and charcoal (real, not briquette). She did this each night and morning for 3 days and the odor was gone.

yes, I've heard of that. I'll try. The fume-like odor IS going away gradually.