Deploy the Mana Thieves

Create a 1/1 black Pirate creature token for each mana in your mana pool, then create a Treasure artifact token with "Sacrifice this artifact: Add
one mana of any color to your mana pool."
Empty your mana pool: Return Deploy the Mana Thieves from your graveyard to your hand. (To empty your mana pool, remove all mana that was previously in it without using that mana.)