>Isn’t it widely recorded that handwashing only came to be a norm mid-1800s?
You're mixing up two completely different modes of washing. The one related to medicine in XIX is about washing hands in lime solution. Pop science magazines always miss this part to make it feel more sensational I guess.
Washing visibly dirty hands (e.g. with soil, grease, or blood), often using sand as an abrasive cleaner, and ashes to dissolve fat, or (depending on one's wealth) a real soap was a norm for a very long time before.
[Edit: added the last para]
You're mixing up two completely different modes of washing. The one related to medicine in XIX is about washing hands in lime solution. Pop science magazines always miss this part to make it feel more sensational I guess.
Washing visibly dirty hands (e.g. with soil, grease, or blood), often using sand as an abrasive cleaner, and ashes to dissolve fat, or (depending on one's wealth) a real soap was a norm for a very long time before. [Edit: added the last para]