From the unaired episode, "The Trouble with Ass-Rubbing Clones"
Scotty: "I gave them a very good home, sir."
Scotty: "I gave them to the Klingons, sir."
Kirk: "You gave them to the Klingons?"
Scotty: "Aye, sir. Before they went into warp, I beamed the whole kit and kaboodle into their engine room... where there'll be plenty of ass-rubbing."