Davin, much old furniture was made using hide glue. This glue is sensative to temperature and water. You might be able to wrap a hot, wet rag around a joint to get it to release but you will also be taking a chance with the finish. Once the piece is apart, you can remove the old glue with sandpaper or something like an X-act-o knife and reglue. I suggest that you consult a book on furniture restoration for some of the tips and tricks on this as there are many for many circumstances.