If you do not have a way to spin it, wrap at least 6 turns of masking tape with it's edge just above the wood on the ferrule.
Then heat the ferrule, you can apply heat with a candle, or even a torch, the tape will protect the wood, if a little common sense is used.
Then take a pair of pliers and gently try and move the ferrule, DO NOT FORCE it, if you do you may break the tenon.
In most cases the ferrule will come off clean the first time along with most of the adhesive, if not heat it a little more.