Things You'll Need
Instructions
Open the lunch box and see if there is a thermos that corresponds to the theme. Check all hinges and fixtures on the lunch box and thermos. Collectible lunch boxes should be in good condition with no rust and all attachments working.
Look for dates or date stamps on the lunch box indicating when it was made. Take photos of the lunch box, thermos, date stamps and all attachments.
Cross reference the pictures and information with the lunch box collector's guide. If no guide is available, take the pictures to an antique shop, or even a comic-book shop as many collectible lunch boxes have "Star Wars" or superhero themes.
Show the pictures to the shop experts and ask if they know whether it is a collectible. Ask what the approximate value of the lunch box would be.