First, let it never be said I passed up an opportunity to make a The Police reference.
Now that we have that over, The Guinness Book of World Records has officiated the oldest note in a bottle ever found. The note is over 98 years old and it is an old National Geographic note from a 1914 scientific study concerning ocean currents. The note asks people to return the bottle to Captain C. Hunter Brown of the Glasgow School of Navigation. Apparently they released nearly 1,900 bottles but only got back a bit over 300. That seems about right for survey return rates, I think