Historical clue formulations

• Junk transporters — 2019-04-14
• Garbage-carrying boats — 2017-05-08
• Garbage transporters — 2016-05-17
• Garbage boats — 2014-06-09
• Junk vehicles — 2010-11-05
• Punts, e.g. — 2009-10-29
• Barges — 2008-05-15
• Tugs' tows — 2002-06-29
• Garbage haulers — 1998-07-26
• Harbor haulers — 1994-10-01