Related Clues:

• Clean the chalkboard
• Make goofs
• Wipe the board
• Wipe the chalk from
• Drop a pop
• Lose points on an exam, say
• ''To ___ is human . . .''
• Make a wrong choice
• Miss a beat, perhaps
• Type a typo
• Transgress, e.g.
• Wipe the slate
• Sudoku solvers often do it
• Be off a bit
• Clear away