They ate off trenchers, hard pieces of bread which you could also eat. No dishes to worry about (and ceramic glazes plus metal utensils are tough to come by anyway).

Soap and water? Soap was known to civilization by ~2000 BCE, long before the middle ages.

Two answers:

- Hygeine? That was invented by Louis Pasteur in the nineteenth century. :)

- In circumstances that allowed it, bread was often used as a plate (“trenchers.”) Would be nicely hygienic if the bread used in this way wasn’t traditionally then given as alms.

Warm water and sand can clean pretty good, too.

I've no special knowledge of such things, but for one I doubt there were many dishes to speak of. Mugs were often used for alcoholic drinks, which I'm sure helped a bit. I imagine utensils were quite rare. Perhaps just a plank of wood would be used, or a hammered flat bit of iron.