I cleaned mine
right after we bought our boat. Granted, it is a 1998 260, but the cabin cushion material is very similar to what I've seen used in older boats.We removed the dark blue cushion covers from the foam pads and zipped them back up, emtpy. We put them 2-3 at a time into our clothes washer, cold water wash, delicate cycle, with an extra rinse. We used about a 2/3 cap of a standard clothes washing detergent.While those washed, I took the foam cushions into the tub and washed them by hand, wrung them out and then took them to the back yard where I hosed them down repeatedly.After a few hours in the warm sun and 75 F degree weather they were dry again.When the cushion covers were done in the machine I put them back on the dry foam cushions and put them back in the sun to dry. A couple of days later I bought some fabric protector spray at a local store and treated the top sides of the cushions, where spills could occur.They smell and feel like brand new. Hope that helps!MikeH