Let her play just like everyone else. I tell parents the same thing, don't send your kids in anything you don't want to get dirty. I had one dcg that used to come in lovely, frilly dresses every day. Her parents would pack a change of clothes and ask me to change her if we were going to play outside. I told them I did not have time to do that, and the change of clothes was for wet or dirty clothing mishaps. They kept sending her in the frilly dresses with the change of clothes. I kept letting her play in the dresses.... and they got pretty dirty some days. Eventually they got the point and started sending her in more appropriate clothing. We don't have time to be changing the dck's clothes everyday unless it's necessary. And I would never hold a child back from playing because they were sent in 'nice clothes'.