This one was from summer break when it was much warmer. I am not particular about the ol’ minivan. My husband would never allow this, but I set them up in swim suits and a bucket of soapy water and let them have at it. As long as they don’t drop the sponges on the gravel then use them to scrub, I think we’re good. You could also let them wash all those other vehicles you have–trike, wagon, big wheel, etc.