depends on the handling. if she's just chilling with me, i don't bother doing anything when i put her back. if i'm cleaning up after her or feeding her i'll wash up afterward (soap and water).
i'm also of the persuasion that too much sanitation is horrible for your immune system (i.e. germs are good for you). there's a higher risk of obtaining salmonella poisoning from a lazy chef at a restaurant than a healthy snake.
in contradiction to that, i wash my hands very frequently, but moreso because of my job than a fear of germs.