I always like to see the look on the face of the AVIS airport agent when I bring my rental car back. Here is a rental from a year ago that got caked in mud. The mud eventually baked in the sun to form very tough crust or outer shell on the car. I am actually quite proud of the offroad mess I can achieve in a few weeks pounding highways and searching for backroad shortcuts. To me, mud is character! It's class! It's sassy!