Make a paste of baking soda and cool water in a small bowl. Moisten a microfiber cloth, and dip the edge of it into the paste.
Scrub both of the soles using a gentle, circular motion. Allow the baking soda paste to sit on the soles for several minutes before wiping it off with a second moist, microfiber cloth.
Wipe the soles with a soft cloth until they are completely dry. Leaving excess moisture on the soles will cause them to yellow further.
Place the sneakers into a sealable airtight container. Add two to three silica packets to the container, and secure the lid.
Store the shoes in a dark, moisture-free environment when not in use. While wearing the shoes, avoid puddles, mud, wet grass and dusty areas.