Related Clues:

• Puts an edge on
• Silvery fishes
• Refines, as metal
• Refines, as ore
• Fuses, as ore
• Runs a refinery
• Makes perfect
• Sharpens, as skills
• Works in a refinery
• Sharpens, as a knife
• Makes keener
• Makes sharp
• Works on
• Zeros (in on)
• Makes sharper