Purchase the products needed for removing leather color. You will need leather prep and an abrasive pad. Check with your local furniture retailer or search online (see the Resource section). Kits are available. However, the kit will come with tools used to re-color your leather and you will end up paying for more materials than you need.
Cover your work area. Use a small tarp or plastic covering to protect the area around your couch from exposure to chemicals. Use gloves to protect your skin and safety goggles to protect your eyes. Chemicals can damage materials in the surrounding area as well as your eyes and skin.
Clean your leather furniture. Take the sponge and wipe down the leather couch using the prep solution.
Take the abrasive pad and work the solution into the leather. This process will remove pigmented color and the manufacturer's finish. Continue this process until the old color is striped and the lighter color beneath is exposed.