Well, I used the vinegar/water solution and steamed it all out. It did seem to get a lot of the gunk out that just rinsing and dumping and steaming with water hadn't gotten.
But WOWEE that vinegar steam will make your eyes water!
So the iron is saved! I don't judge anyone else on what they would have done with their iron, but I'm just to cheap to toss it without trying other stuff first.