If they're rusted in, and if you can tolerate putting whatever they're rusted into in water (at least that part of it) you might try electrolytic rust removal. You can do a search on the web for the instructions. Basically, you use a battery charger, water and washing soda from the supermarket to remove rust from one iron/steel item and in the process turn another iron/steel item into rust. Unfortunately, it doesn't turn rust back into metal, but it won't remove anything but the rust. It will take plating and paint off metal if they aren't on there pretty good so I don't put anything in with a finish I want to save on it. Real important to get things hooked up right, but it can turn some really ratty looking items into something that looks halfway decent. It might remove the rust around the pin and allow you to get it out.
Alan