Historical clue formulations

• Locks that might not be totally secure? — 2019-08-02
• "Rugs" — 2017-09-21
• Alternatives to plugs — 2017-02-10
• Top secrets? — 2017-01-19
• Top-secret disguises? — 2015-05-15
• Alternatives to comb-overs — 2013-02-03
• "Rugs" — 1996-07-15