Remove any cushions or pillows from the sofa.
Vacuum the sofa and cushions thoroughly with an upholstery attachment. This prevents the steamer from clogging with pet hair or lint during the cleaning process.
Fill the steam cleaner with hot water and upholstery cleaning solution according to the manufacturer's instructions.
Clean the sofa with the upholstery attachment according to the manufacturer's instructions. Work on one small area at a time, starting at the top or back of the sofa. Dispense enough solution to thoroughly wet the upholstery, scrubbing with the attachment as you go.
Empty the steamer and refill it with clean water. Repeat the cleaning process with pure water to rinse the sofa of any product residue.
Open any windows and turn on a fan to speed up the drying time. Depending on the type of fabric and amount of cleaning needed, the sofa could take up to a day to dry.