I'm not sure. I think use soft cloth.I think there is a self wash place north of Knauz on 41 too. Not 100% sure, haven't been up that way in a while.

I strictly use touchless in winter time. No cloth for me.

For sand or light mud we use a round plastic lawn sprinkler. Slip a piece of PVC over the hose, attach the sprinkler, grab the hose wherever the pipe ends, and turn the water on. Saves bending under the vehicle in a freezing car wash bay.