Ive cleaned a couple of pairs with the hot solvent through my ninja in the garage, not keen at all,certainly wouldnt want to use the system in a customers house,even with the garage door and window open the fumes built up in there, you would only need a spark (cigarette or light switch etc switched on) to have a a nice big fireball,i talked to several people who own them before buying it and they all said the same thing, rip it out of the machine, at least it makes it lighter for lifting in and out of the van!!