"The very thing.

Why did I not think of it myself ?" So he summoned his soldiers and retainers and bade them prepare a great bonfire in an open space in the castle park.

Also he sent word to all his people to assemble and witness the destruction of the Scarecrow who had dared to defy his power.

Before long a vast throng gathered in the park and the servants had heaped up enough fuel to make a fire that might be seen for miles away--even in the daytime.
When all was prepared, the King had his throne brought out for him to sit upon and enjoy the spectacle, and then he sent his soldiers to fetch the Scarecrow.
Now the one thing in all the world that the straw man really feared was fire.

He knew he would burn very easily and that his ashes wouldn't amount to much afterward.