This line in Millard Fillmore's first message to Congress will definitely require some further research:
Peruvian guano has become so desirable an article to the agricultural interest of the United States that it is the duty of the Government to employ all the means properly in its power for the purpose of causing that article to be imported into the country at a reasonable price. Nothing will be omitted on my part toward accomplishing this desirable end.
Fillmore has become the poster child of presidential mediocrity; even the official White House biography calls him an "uninspiring man." And Captain Charisma's last words - "the nourishment is palatable" - were about soup.
But guano? In a message to Congress? Actually, guano was hot stuff for farmers back in the day, and with that in mind, you can see the above paragraph as a trade policy of some seriousness.
That said, it is likely the one and only time you'll see a president of the United States refer to bird droppings in a message to Congress. if there is a better metaphor than guano for Millard Fillmore's historical reputation, I have yet to see it.