Blot up the excess Coke, using white paper towels. Absorb as much of the soda spill as possible.
Fill a spray bottle with cool water. Spray the Coke stain with the water, lightly moistening the upholstery. Let the water permeate the dark soda stain for 1 minute.
Blot the moistened Coke stain with a fresh paper towel. Absorb as much soda as possible.
Inspect the sofa upholstery for Coke. If the dark spill stain remains, add 1 tablespoon of non-bleach dishwashing soap to a container, and add 2 cups of cool water to the container.
Stir the dishwashing soap solution until thoroughly mixed. Moisten a white cloth with the mixed solution.
Blot the remaining Coke with the moistened cloth until the dark blemish dissolves. Fold the cloth frequently while blotting so you're always using a clean portion of the cloth.
Dampen another cloth with cool water. Tamp the previously Coke-stained upholstery until thoroughly rinsed. Flush out the detergent residue.
Blot the moisture off the sofa’s upholstery, using a white towel.