24. War posters
History buffs love to collect classic war posters. These are highly sought after, often reprinted in modern times. So if you find a sign in your home, make sure it's a real vintage poster or a replica. If you have an actual poster, you can sell it for a few hundred dollars to a collector.
Make sure your poster is still in good condition. Folds, wrinkles, tears, and water damage can all damage the paper product. It is normal to change color over the years, but a well-preserved poster can be precious.
