Wipe down the affected section of sofa with a mixture of one-half tablespoon liquid dish soap and 4 cups lukewarm water. Dampen a soft cloth with the solution and wipe away dirt, grime or dust. Remove the soapy residue with a separate soft cloth.
Cut around the damaged area with a utility knife to create a small, even hole. PVC upholstery features a fabric backing that can leave behind stray strings. Cut away these strings with a small pair of scissors or nail clippers to create a smooth finish.
Locate a piece of matching vinyl upholstery from scrap vinyl or an unnoticeable section of the couch, such as the underside or back. Cut out a piece of upholstery that is slightly larger than the hole created in Step 2, using a utility knife. Remove any strings from the fabric backing with the small scissors.
Press the vinyl patch through the hole with a finger. Manipulate the patch until it is sitting flat inside the hole and free of creases or bumps.
Apply a thin layer of vinyl adhesive, available at hardware and home improvement stores, around the perimeter of the patch. Allow the adhesive to cure according to the package directions.
Cover the seam created by the patch with a thin layer of vinyl colorant. Apply the colorant with a rag and allow it to dry completely, or according to the package directions, before using the couch.