Are you asking about vinyl or cloth material? I will assume cloth. Whatever you try, test it on a non conspicuous area first. A lot of the manufacturers do not recommend washing.. That said, many folks(like me) do use a wet rag or even a soft brush with a light soapy water solution, just don't soak the cushions. Rinse a few times by wiping with a wet rag Be careful with any cleaner that has bleach. In addition to possible bleaching out the color, bleach can speed up the aging of the threads. Start will mild cleansers and go to stronger if needed. Sometimes the upholstery cleaners sold in the supermarkets work well. If the cushions smell, that may be really hard to remedy if the internal foam is very moldy. For not so terrible odors, try Fabreeze spray. Sometimes just placing in the sun for a while helps especially for drying after 'washing'