Possible Clues:

• Strike together, making nasty wound round knight
• Grind, emptying out green powder
• Grind one's molars
• Grind teeth together
• Strike against
• Cut around the base of horn and grind
• Belted out review hard on the grind
• Hangs out - it's what one does after a hard grind?
• Grind, as molars
• No! Time flies before hard grind