Historical clue formulations

• Courageously persistent — 2017-05-02
• Strongly realistic — 2010-11-26
• Strongly realistic — 2008-06-20
• Not completely dissolved, as a drink mix — 2004-12-06
• Like sandpaper — 2003-02-26
• Tough and courageous — 2002-03-17
• Resolute — 1998-04-23