How can I get mold out of my leather couch?

There is no way to completely remove mold growth from leather and it is recommended that you dispose of the material. If you insist on keeping the material(s), try this: For surface growth, as a result of humidity, try cleaning mold growth off the surface using a soap/detergent solution (don't need bleach). For extensive mold growth on leather, replace the affected materials if you can (cut out and patch) or clean it, dry it completely, and encapsulate it with another material. Materials that have been in contact with "grey" or "black" water (i.e. sewage) should be disposed of. Always wear proper personal protective equipment (respirator, gloves) when handling moldy materials.