Historical clue formulations

• Marks taken off? — 2015-08-09
• Indications that things have changed? — 2009-07-18
• What smudges may indicate — 2003-07-24
• Errata reducers — 2002-04-26
• Wipeouts — 2002-03-28
• Signs of censorship — 2001-04-15
• Strikeouts? — 2000-07-15
• Crossword solvers' smudges — 1999-03-16
• Evidence of changes — 1998-08-15