I removed the covers from all of my cushions and threw them in the washer on gentle cycle using a gentle soap. I then let them air dry. For the foam, I bought one of those plastic kiddie pools and filled it with water and a VERY diluted mixture of bleach and vinegar. Then, one piece at a time, I would thouroughly saturate the foam in the solution then let it soak for 10 or 15 minutes. After soaking, I rang the water out as best as I could and let the foam air dry (this took a few days). The end result was clean, non-smelling cushions.
Catalina 38, Hull #112
Grosse Ile, Michigan