I am trying to raffle off a bottle of Dry Sack Sherry produced and bottled by Williams and Humbert, Jerez and London, imported from Spain, at least 35 years old. Has been stored by a former liquor store owner all these years. Though it is tightly sealed on the outside, if there is a cork, it appears to be very mildly leaking if tipped. Is this any good or will it be poisonous? Please help.