Organic substances will not, for the most part, dissolve in H2O. But they will dissolve in EtOH. Balsam, resins, saps, sugars, esters, etc. will readily dissolve in EtOH. A possible issue is that some sap/resin/oils leached out over time and are acting as a light glue, holding the tube and stem together with the shank. Maybe. Adding the grain may be enough to dissolve the "glue" enough to loosen its grip. My 2 nos Dublins have a tube and were stuck. Alcohol worked a charm but ymmv and it may be a waste of time. Is there a possible downside to adding the alcohol?