Olly & Alex go head-to-head at The Human Carwash. A question will decide who goes in the carwash and who sits in the gunge tank. The loser (who will ride the carwash) will get to choose an envelope to decide where the mystery ropes at the end are connected up to. One will pull the grand finale in the carwash device, the other may be connected to the gunge tank or even above presenter, Zane. All to play for!