Would you please publish the enclosed manuscript or return it without delay, as I have other irons in the fire.
Source, in full
A covering note sent with a manuscript submission, which was supposedly returned with the answer, "Put this with your other irons." The same story had much earlier been told about Dr. Johnson and Mrs. Piozzi in Kate Sanborn Home Pictures of English Poets (New York: Appleton, 1869) p. 215.