Maintain a regular cleaning routine of your leather upholstery so it will not look dull and tired. The best thing to use is a damp cloth to get rid of soft stains and dust.
Any stain on leather has to be removed as soon as possible. If the stain is not too big you can use baby wet wipes. It will leave also a very nice smell!
For water based spills or stains, use a soft cloth to absorb the excess and allow to dry for three or four days. If the stain is still visible, you can polish the area very gently with a clean dry cloth.
For oil based spills or stains, use a mild soap and then rinse the area with clean water. Allow to dry for three or four days.