Wipe the scratched area with a cotton cloth to ensure that the area is free from dirt or debris. It is important to avoid creating new scratches during the repair.
Wet the scratched area with water. The water will act as a lubricant for the sandpaper.
Brush the damp, scratched area with an 80-120 grit sandpaper pad. Be sure to follow the grain of the fixture in order to prevent future scratching during the sanding. Sand until the scratch is no longer visible and the edges of the sanded area blend in with the rest of the fixture.
Rub the sanded area with the cotton cloth to buff the fixture and create a shine. This may take a few minutes of rubbing to achieve.
Apply enough vinegar to cover the buffed area. The vinegar will help remove any oil or other debris left on the fixture from the sanding and buffing process.
Wash the vinegar off of the treated area with water. You may need to use a soft, damp cloth.
Dry the treated area with the cotton cloth.