Historical clue formulations

• Remains of a wreck — 2017-10-13
• Detritus at sea — 2017-08-07
• Refuse on the surface — 2015-01-09
• Jetsam's partner — 2009-11-02
• Refuse at sea — 2002-01-20
• Refuse — 1999-11-19
• Ocean debris — 1998-10-05