We have a 1999 Troll and I washed the covers twice in the past (before reupholstering because we added memory foam). I didn't do the back seats that are stapled onto the base, but the rest had zips. They all went into the washing machine on a cool wash, and then the tumble dryer. After that it was a bit of a struggle to get them back on, but if you bend them in half they go back on OK. Everything fitted fine and they washed well. I don't know if your fabric is very different, but if they have zips, I imagine that they are intended to be washed no problem.