Anyone have tips for separating a riser from a log manifold? I shot the nuts with penetrating oil for a couple days, and finally got them off. The studs dont look too bad, but some corrosion is visible. It didnt look bad enough to make me think it would be stuck once I finally got the nuts off, but its stuck. I took a few decent whacks with a rubber mallet and it seems pretty well stuck. I lightly tapped a chisel between the stud end and the riser to wedge it off, no luck. Anyone know of a penetrating oil that will 'eat' the corrosion by-products away? Or some other whack location that might get these things separated?