Hmm, I thought there were several scenes of Captain Jack sifting through the treasure and tossing most pieces over his shoulder. I assumed that he was sorting the Aztec gold from other miscellaneous loot, because it was never specified that the only cursed stuff was in the chest, it was just the last pieces the could find.
At least that is my brain trying to make the whole story work.
Actually, the rest of the treasure was simply stuff Barbossa's crew had accumulated throughout the years of raiding and searching for the cursed gold. They couldn't enjoy the fruits of their labors properly, so they'd squirreled it away for when they finally managed to lift the curse. That's what I'd concluded, from the dialog.
