Here are some ways to polish a knob:
- Brass or copper knobs
Make a paste of equal parts flour, salt, and vinegar, apply it to the knob, let it sit for a few minutes, and then buff it off. You can also use a powdered or liquid cleanser like Bar Keepers Friend, applying it to a sponge or soft cloth and gently working it into the knob. For hard-to-reach areas, use a soft-bristled toothbrush.
- Bronze knobs
Mix one part detergent or soap with ten parts water, apply it to the knob with a soft cloth or old toothbrush, and then buff it with a microfiber towel or chamois cloth.
- Tarnished brass
Make a paste of half a lemon's juice and a teaspoon of baking soda, apply it to the knob with a soft cloth, and let it sit for 30 minutes if the tarnish is heavy. Rinse with warm water and dry.
- Rubbing alcohol
Polish the knob with rubbing alcohol and a microfiber towel.
You can also use a sisal buffing wheel or a firm airway buff with an abrasive buffing compound to remove fine scratches. For a final polish, you can use color buffing to bring out the metal's luster.