<human>:  I have a stain on my leather sofa, what's the best way to clean it?
<bot>: The best way to clean a stain on a leather sofa is to use a damp cloth and a gentle leather cleaner designed specifically for use on leather upholstery. Test an inconspicuous area first, and if it is safe, gently rub the cleaner into the stain using a circular motion. Let the leather cleaner sit for a few minutes and then wipe it off with a damp cloth. Finally, buff the area with a dry towel to remove any residue.