We cleaned ours by removing the covers (those went into the washing machine with Clorox Color-Safe bleach, detergent and some Febreeze fabric softener) and washing the cushions on the dock in a huge cooler (couldn't find a kiddie pool) with with the Oxy Clean and Clorox Color-Safe Bleach (seems less harmful to the foam.) It was done on a hot day with no humidity, so they dried pretty fast. Man, if you could have seen how disgusting the water was... Anyhoo, the end result was awesome- the cushions actually smelled good, and another source of boat funk was gone. It's amazing how much stink the cushions can hold!
Chris
US 30' Wu-Wei
http://www.diysailor.com