I picked up some carbs for dirt cheap at a yard sale. One is a Holley 4150 and the other is a 1.08 Autolite 4100 for an auto trans. Both have the butterflies frozen/locked up. The Holley is due to rust, and it looks like the Autolite is due to corrosion. Is there a good way to free up these things for rebuild, or should I just consider them parts carbs? Penetrating oil didn't work on the Holley.