Throw'em to the Wolves

"Harry: "We'll take him to the castle." Wormtail: "Oh bless you boy, bless you!" Harry: "Quiet! I said we'd take you to the castle. After that, the dementors can have you.""

- Harry Potter and The Prisoner of Azkaban

A way for The Hero to dispose of a villain without getting blood on his hands. Rather than the hero doing justice onto the villain (or what have you) himself, he decides to do it indirectly, by leaving him in the not-so-good hands of someone with fewer qualms about...harsh justice. Note that this is the hero's doing; this does not apply to the common situation of a villain leaving the hero at the mercy of his Mooks.

Do with Him as You Will, where The Hero turns the villain over to the villain's former victims, is a subtrope of this. All instances of that should go on that page, not this one.

In short, it's in the middle of the Sliding Scale of Idealism Versus Cynicism; The Hero doesn't actually kill the Big Bad, and the Big Bad gets a Karmic Death...but one that The Hero throws them into.

'''As a way for a villain to meet their demise, this can easily be a Death Trope. Expect unmarked spoilers.'''

Anime and Manga

 * In an episode of Naruto, Choji remarks about one suspect in the tracking of Hidan and Kakuzu, "We'll leave the torture to Ibiki."

Comics

 * One Authority story has a Captain America (comics) knockoff beating the crap out of Apollo. At the end, said knockoff is paralysed and taunts Apollo into killing him. Instead of killing him, Apollo just says he promised him to someone else. Cut to Midnighter, wielding a jackhammer. "A pleasure to finaly make your acquaintance" indeed.

Television
"Mal: I got to know... how much you told them. So I've given Jayne here the job of finding out. Jayne (pulling a knife): He was non-specific as to how."
 * Mal leaving Dobson with Jayne in Firefly:

Film
"Pushkin: Send him back to Moscow. In the diplomatic bag."
 * In The Living Daylights, James Bond hands General Koskov over to the Russians he defected from originally.


 * In the remake of The Italian Job, the villain is handed over to the Ukranian gangster whose brother he murdered. He faints on being told what will be done to him.

Video Games

 * In Uncharted 2: Among Thieves, at the very end. Lazarevic, the final boss, has finally been defeated, but he pulls an If You Kill Him You Will Be Just Like Him, basically telling Drake to gun him down, without hesitation or mercy, since that fits with his own philosophy. Drake, however, refuses, and when Lazarevic gloatingly states that he "does not have the will", Drake just agrees but comments "But THEY do..." and then quickly leaves as about a dozen of the monstrous, nigh-unkillable Guardians of the Tree arrive to tear him to shreds for trespassing on their holy ground.

Serials and Literature

 * A Judge Dee story ends with the bad guy confessing freely admitting his murders. Being of the Screw the Rules, I Have Connections type, any accusation would end with him getting away free and destroying the judge's career, so the judge fools him into entering a small courtyard containing a bear and locking the door. Said bear was earlier shown to leave those he liked alone and maul the rest, leaving the bad guy some chance.
 * In Harry Potter and The Prisoner of Azkaban, Harry convinces Lupin and Sirius to spare the traitorous Wormtail's life, arguing that the friend they wanted to avenge (Harry's father) wouldn't have wanted them to become murderers. Wormtail obsequiously thanks Harry for his mercy, only for Harry to snap back that he fully intends to turn him over to the Dementors. Of course, in the Wizarding World, the Dementors are the justice system, so it's really the only other option.

Webcomics
"Kevyn: We are going to turn Shufgar, alive and healthy, over to the Judges of House Est'll. Kevyn: Then, per ancient tradition, he will be killed and eaten a little bit at a time. Brad: Your place sounds darker, sir. Kevyn: It has the advantage of being legal."
 * One of the arcs of Schlock Mercenary has a group of mercs under the leadership of Kevyn get captured by the pirate captain, Commodore Shufgar, who proves remarkably cruel, and successfully kills at least one of them. (He also kills Kevyn. Several times. But it doesn't take...) At the end, when they've turned the tables and captured the captain, the men are all-too-eager to dispense their own, personal justice for their fallen comrade, but Kevyn warns them off, saying that that road leads to "A dark place".