My grandma had a painting of an old ship hanging in their house. My dad removed the backing just enough to hide the map behind the ship. When he tried to get the map out many years later, he found that time, age, and the elements had fused the backing to the painting and he was unable to remove that map.
I have the painting with the map still hidden behind it. It's a treasure for me because of the story behind the painting. The jar of pennies is long gone, I'm sure, the map no longer useful since he has died and no one else knows what it says. But that treasure map leads to a much larger treasure for me. A look into my dad's childhood that was full of work around the home place, odd jobs to make ends meet, and tragedy when his dad died early in his life. That he could still be a little boy, with dreams of buried treasure and hidden maps was a a testament to the resilience of a child.
And the painting? It's an old ship. Looks like one a pirate might have captained. That makes me smile.