Dampen a clean white cloth with cool water. Blot the fabric with the damp cloth to remove the excess WD-40. Continue blotting for several minutes. Pat the fabric dry with a towel.
Pour distilled white vinegar in a clean spray bottle. Mist the smelly couch fabric with the vinegar and let dry. The vinegar will eliminate odors -- including those caused by WD-40 -- as it dries on the fabric. Reapply the vinegar if the WD-40 smell remains.
Sprinkle a box of baking soda over the dry couch fabric. Scrub the baking soda into the fibers with a soft-bristled brush. Let the baking soda sit on the couch for several hours. Attach an upholstery brush to the vacuum hose and remove the baking soda off the couch.
Fill a clean spray bottle with 1 cup of cool water. Add 10 drops of lemon, orange or tea tree essential oil to the water. Secure the top on the bottle and swish the contents together for several seconds. Mist the couch with the homemade odor remover and let air dry. The mixture will remove odors while replacing them with a fresh and pleasant scent.
Purchase a commercial odor remover and mist the couch fabric thoroughly. Let the odor remover dry on the sofa and repeat the process if needed.