The 'gunge' was a food thickening agent called Natrosol, coloured with various food dyes. The gunge tank got progressively more sophisticated. From Series One a standard tank was used, with an ornate look to it. Series Two introduced foam (often coloured) rising up from the bottom prior to the gunging. Series 3 introduced the 'Car Wash', where the individual was carried along a lengthier tank, going through a set of brushes designed to soak the victim, then having the gunge descend from above before being spun out of the contraption. In series Four and Five, it was developed into the 'Trip Around The Great House', where the victim was placed on a miniature railway that took them on a journey around the set, finishing up in the giant fireplace, where gunge was finally released onto the victim. From Series Six, there were changes to the format, and gunge was used less frequently. For Series Eight, a member of the audience would be gunged by a tank lowered from the studio rafters, or their chair would be lowered into the undercroft of the seating area, where they were gunged, and came back up again.