<human>: What's the best way to clean a tarnished brass doorknob?
<bot>: The best way to clean a tarnished brass doorknob is to mix equal parts baking soda and water, then apply it directly onto the tarnish with a soft cloth or cotton swab. Allow it to sit for at least 30 minutes before wiping away any excess residue. Rinse off the area with warm water and dry thoroughly with a soft cloth.