Hi mate, I use some auto smart upholstery cleaner mixed quit strong in the karcher extractor, I do not like getting seats to wet as it degrades the foam pads to much but as this was for one of our works colleagues I said I would do it, I have to view each job differently but definitely would not want to increase the chance of damaging any of the materials that I clean, for friends we sometimes with their permission, take the chance, these seats were scrap anyway so nothing lost if they fell to bits lol.