Don't forget to specify with soap and to do it after bathroom visits and before meals, otherwise they'll just wash their hands once per month and use dirt to wash with.
And specifically before they try any "surgery"
did they have soap back then?
According to Wikipedia
Humans have used soap for millennia; evidence exists for the production of soap-like materials in ancient Babylon around 2800 BC.
"wash your hands"
Don't forget to specify with soap and to do it after bathroom visits and before meals, otherwise they'll just wash their hands once per month and use dirt to wash with.
And specifically before they try any "surgery"
did they have soap back then?
According to Wikipedia
So I think they did.