The answer is: Gave them back

Matt 27:3-4 - He threw them down in front of the chief priests and elders, and being tainted money they decided they couldn't put it in the treasury and so bought a field instead in which to bury strangers

Judas Iscariot’s 30 pieces of silver serve as a compelling thread woven into the narrative of betrayal and regret in the Gospel of Matthew. This infamous transaction highlights not just a sacrifice of loyalty but sparks significant ethical questions about money and morality. Returning this blood money, Judas dramatically throws the coins down in disgust—not exactly what you’d expect from someone most view as a hardened traitor. It illustrates a profound moment of realization that possession of ill-gotten gains doesn't bear the sweetness of success, but a truly heavy weight that can lead one to madness.

Interestingly, the amount he received, 30 pieces of silver, mirrors the price for a slave in ancient Israel, as Genesis 37:28 and Exodus 21:32 hint. What adds another layer of irony is that these coins ended up funding a burial plot for the outcasts—a twisted twist of fate, given how Rover, or Jesus, became just as much an outsider after his crucifixion.

Curiously, that field repeated the narrative of prophetic fulfillment drawn from Zechariah 11:12-13, which calls into question the interplay of fate and choice in this powerful drama. The idea that something so devastating as betrayal leads to decisions impacting communities ties the past, the unpredictable present, and the imaginations of future generations. Ultimately, Judas is both a deeply human character facing monumental regret and the emblem of choices that reflect broader ethical questions today.