Historical clue formulations

• Symbol of strength and solidity — 2026-07-09
• Material refined through the Bessemer process — 2025-11-07
• Source of Andrew Carnegie's wealth — 2025-05-01
• World's most recycled material — 2024-10-06
• Famed Damascus product — 2024-05-26
• Iron/carbon alloy — 2024-04-01
• Prepare (oneself) — 2024-03-03
• "Stainless" metal — 2023-05-16
• Prepare (oneself) — 2022-08-27
• Material for some drums — 2022-06-12
• Construction beam material — 2022-05-30
• Metal for a girder — 2022-04-18
• Symbol of strength — 2022-03-18
• Word with guitar or wool — 2021-04-21
• Bethlehem ___ (old company) — 2020-11-25
• Stainless ___ — 2020-11-17
• Gird (oneself) — 2020-08-12
• Classic Pittsburgh mill product — 2020-07-21
• What recycling code "40" is used for — 2020-06-05
• Gird (oneself) — 2020-02-23
• Shade of blue — 2020-01-21
• Source of Andrew Carnegie's fortune — 2019-12-01
• Product Pittsburgh is famous for — 2019-09-23
• Symbol of strength — 2019-05-05
• Bessemer process output — 2019-02-22
• Shade of gray — 2018-03-10
• Resolve — 2018-02-18
• Symbol of strength — 2018-02-02
• Shade of gray — 2017-03-26
• Toughness — 2016-08-04
• Gird (oneself) — 2016-07-20
• Product of the Nucor Corporation — 2015-09-15
• Longtime Pittsburgh product — 2014-09-29
• Stainless ___ — 2014-04-07
• Andrew Carnegie's industry — 2013-10-09
• 1943 penny material — 2013-10-01
• 1943 penny composition — 2013-06-30
• What tuning forks are made of — 2011-08-19
• ___ blue — 2011-08-14
• Word with plate or plant — 2011-02-20
• Bethlehem ___ — 2011-02-09
• Coke is used for this — 2011-01-27
• 1943 penny material — 2010-06-30
• "Stainless" metal — 2010-02-01
• Many a shipment to Detroit — 2009-12-06
• Mettle or metal — 2009-11-01
• Sword material — 2009-05-31
• Nerve material? — 2008-08-31
• Pittsburgh product — 2007-05-22
• Mill output — 2007-05-08