Historical clue formulations

• Improves, as a skill — 2024-01-08
• Works at the cutting edge? — 2021-11-07
• Gives an edge — 2021-06-27
• Perfects, as one's skills — 2015-09-28
• Improves — 2014-09-26
• Perfects — 2014-09-25
• Sharpens — 2012-08-13
• Puts an edge on — 2011-09-29
• Practices — 2011-07-10
• Sharpens — 2011-07-04
• Improves — 2007-06-08
• Works on — 2007-02-04
• Sharpens, as a knife — 2006-10-03
• Sharpens — 2005-06-20
• Sharpens — 2001-03-13
• Whetstones — 2000-06-04
• Practices — 2000-03-12
• Fine-tunes — 1998-02-06
• Sharpens — 1997-06-24
• Sharpens — 1996-11-04
• Sharpens — 1996-03-12
• Maximizes effectiveness, as of skills — 1996-02-25
• Perfects — 1995-08-04
• Sharpens — 1995-06-29
• Sharpens — 1993-12-08