The shaft gets choked up with cooked on carbon which is a very hard, durable and almost impervious to solvents. Since it is created by heat, it won't melt by adding heat.
Having said that, the combination of everything which HRL just suggested will eventually break it free. Don't be in a hurry. You will just make it angry.
Kroil is absolutely amazing. It is the Chuck Norris of the penetrating fluid world. I used to think the same thing about PB blaster. It is like spitting on rusty parts when you can't make any spit compared to Kroil.
The cooked on material is hard and therefore brittle, so firm blows with a medium sized hammer, striking each end of the shaft back and forth will improve the penetration of the Kroil.
Carl
