I've been lucky to always have hunted deer and cold climates, so, if one had to be found the morning after the kill, it was always ok and good to eat. On the other hand, anyone who kills a deer and retrieves it right away should gut it immediately regardless of where he or she lives or whatever the temperature. Not doing that is irresponsible and disrespectful to the deer. Also, in many states, including my home state of Montana, it is illegal to waste game, and like breaking any law, ignorance is no excuse. Every hunter needs to know the basics BEFORE even entering the woods, and how to care for the meat of game animals is part of the preparation package.
To answer one of your questions specifically, once meat has gone bad, there is NO amount of washing or cleaning that will restore it. On the other hand, if good meat gets dirty (stomach contents, or other) it can be washed with cold water and then dried with paper towels, etc. The biggest contributors to meat spoilage are heat, time, dirt and moisture. The more of those things that are present, the faster the bacteria grows and the faster the meat deteriorates.
To answer one of your questions specifically, once meat has gone bad, there is NO amount of washing or cleaning that will restore it. On the other hand, if good meat gets dirty (stomach contents, or other) it can be washed with cold water and then dried with paper towels, etc. The biggest contributors to meat spoilage are heat, time, dirt and moisture. The more of those things that are present, the faster the bacteria grows and the faster the meat deteriorates.