I use soap and water inbetween handling different snakes and after cleaning cages, but for two different reasons. I'm not worried about getting sick from the snakes, but I don't want them to pass anything between each other. For the cleaning poo it's for my own health, since I clean with my bare hands and paper towel.

I try to never use hand sanitizer unless its critical...you use that stuff and you kill all the good germs along with the bad, and therefore risk immunity.