On my recent trip on the SWC from Chicago to LA where I and my travel partners were downgraded to coach after our California Zephyr was cancelled, I had fresh clothes daily and was able to wash up without any problem. Drying off was another matter, as it was very short notice that we were rerouted and didn't have towels with us. Extra deodorant, along with taking more time brushing my teeth and using mouthwash didn't hurt either. Other than the guy who at first sat next to me then (thankfully) moved, who reeked to begin with and who didn't change clothes the entire trip, I didn't notice any unclean passengers amongst the coach car I was in.