I have a stem stuck in an old Raleigh. It is a steel frame, aluminum stem, steel expander. Expander and bolt are free. I have poured a combination of ammonia and drain cleaner into this thing from the bottom of the fork and let it soak for over 6 months. I switch back and forth between the two and leave the frame upside down. I now have transmission fluid in it for a couple weeks. It is still stuck. Time to progress to lye/sodium hydroxide? I mean really...how long should this take?