Related Clues:

• Wear down little by little
• Bite like a beaver
• Chew on celery, e.g.
• Nibble away
• Prey on one's mind
• Emulate a beaver
• Wear down
• Work like a beaver
• Bite away at
• Chew on
• Be beaverish
• Trouble persistently
• Chew like a mouse
• Be an eager beaver?
• Rodents do it