Crazy question: a friend's mom was cleaning out her basement and found two full wooden barrels of "indeterminate age and origin" full of cider. My friend suspects they are at least 35 years old. The barrels have not been tapped, and are airtight. She would like to know: a) are they safe to drink, b) will they taste horrible, and c) would I like them. I have limited experience with cider, and none with anything this old. Anybody have any ideas?