When I worked for Safety Kleen years ago, that was the parts cleaner that took the Zep idea of cleaning the solvent and took it to the next level. It did seem to keep the solvent clean....a lot of transmission shops had them and they seemed to work good. Just the initial expense when they were new never seemed to quite balance the cost of fresh solvent and disposal. They were very expensive when they were new! Picking one up for a couple hundred you shouldn't go wrong.