Why do Eliezer and the other prisoners clean the block right before their departure, and what does it say about the men’s state of mind?

The prisoners prepare for their journey with food and extra clothing. They go to sleep for their last night in Buna. The next morning Eliezer wraps his foot and tries to find more food. The head of the barracks orders the block thoroughly washed so that the liberating army will not think that animals had lived there.