You should be able to work it free by twisting it back and forth while pulling at the same time. There will be a plastic bushing inside too which will need to be removed also. When you start scraping, it will become clear how the salt has built up. Have fun.
I think that CLR, may be hard on the cast aluminium. Which is why I suggested the Vinegar, works wonders on the Salt, welding smoke residue, bird chite....Would soaking the mechanism in something like CLR possibly work? Just a thought. I know the vinegar works well. I used it to clean up a swack of lures and other gear that had forests of salt crystals growing on them.
Like I said earlier, there was a surprising amount of salt in there. Makes me wonder (worry) what else that stuff is getting into and forming on!