Possible Clues:

• Use sandpaper
• Scrape, wear away by rubbing
• They say it's a plait to wear down
• Wear a well-trimmed beard
• How your Da might scrape his way in with the bear
• Use a file, e.g.
• Wear a plait, say
• Wear away (by friction)
• A beard (anag.)
• Wear away by rubbing (6)