Vacuum the top surface of the sofa cushions to pull up hair and debris. Remove one cushion at a time and vacuum over the bottom side of the cushion and sides. Set each cushion aside in a stack and continue until you remove all of the cushions. Vacuum the body of the couch to suck up other debris.
Run a lint roller or use strips of masking tape to pull up any stubborn crumbs or pet hair the vacuum couldn't lift. Unzip the back side of each cushion to remove the cover. Wash the fabric cover in your washer and dryer using your preferred laundry detergent and medium to low heat.
Fill your bathtub half full with warm to hot water and a quarter cup of detergent. Wash large cushions one at a time or two small to medium cushions at a time if they can fit into your tub. Agitate the soap and water with your hands and punch down into the cushion material to thoroughly wash it.
Drain the soapy water and refill the tub with clean water. Rinse the cushions and drain out the water again. Press the cushions to release any excess water.
Spread a clean sheet out over your deck or lawn in a sunny area. Lay the cushions out over the sheet in a single layer to dry in the sun. Flip the cushions every hour to thoroughly dry them. Replace the covers back onto the cushions and zip closed before setting back on your sofa.