I will give you several hints, and the solutions. If the pirates on Spoon Island buried the treasure already, you can make them bring it back. Just talk to them.
Maybe you have something that will help you know where the treasure chest is buried.
Maybe something that will call your name when you are near it?
First solution:Use the pyrite parrot with the treasure chest on Spoon Island.
You know what you need, but the pirates won't let you put it in the chest... maybe you can make them turn around for a moment?
Maybe they can play a game that will make it easier for you to hide the parrot in the chest?
Maybe something that involves their eyes?
Second solution: Talk to the pirates and suggest that they play a game to help them decide who gets to bury the treasure, then tell them to make a staring contest.
They're still looking at the treasure chest so you still can't put the parrot in the chest... maybe you can make them turn around...
Final Solution: Look behind you, a three headed monkey!