I’m assuming the mag tube won’t move because it is stuck in the ring.  Do as Mike said, soak it.  Then try to spin it a little.  Keep soaking it and trying to turn it until it will turn.  You have to clean all around both sides of the ring/tube. Then pull it out a very small amount and clean all around. Push the tube back in so the oil goes under the ring.  Keep soaking, cleaning and pulling until your are sure oil has gotten completely inside the entire ring and all the crud has been removed.  If you don’t take your time to remove the crud on the tube or in the ring you will swirl the tube.