I took the 15 yr old with me today, and we began a deep clean. It needs it. I plan on cleaning every square inch. The wall behind the front bed turned my white rag brown in a hurry. All the interior caulk is going from grime gray to bright white! Very satisfying. Hope it's not all for nothing. I know they are not exactly air tight when being towed. I'm sure that's how a lot of grime gets in.