Thanks alot guys for the suggestions. It i going to be a small matchbox size car. Some of the belt ideas were great, we are going to try them. There will be no water sprayed on them, just simulated. We are building it out of plexy glass encasing. Have the belt running down the middle, with the car glued in place. It will have 3 stages, first stage will be the brushes that spin, 2nd stage will just be an LED to simulate waxing, and the 3rd stage is a small PC fan is going to be mounted to simulate drying. At each stage sensors are going to be placed to turn on/off different things.
Thanks again