They Were Cleaner Than Many People Think
The notion that a castle is a chilly, damp, filthy, and uncomfortable place seems to be well engrained in contemporary thought. In medieval Europe, how could a stone building be anything else? The big and well placed stoves as well as the wall tapestries would have done a respectable job of warming and insulating the portions in which people were living, even though they were probably very cold in various regions during the winter. Nonetheless, a castle was actually fairly well equipped in terms of cleanliness.
The wooden seat above the hole in the castle facilities was extremely reminiscent of an outhouse. Everything that fell into that hole would have fallen out and away from the castle since the hole was constructed in such a way that it was pushed out from the castle wall. This demonstrates the obvious fact that the moat and surrounding terrain were by no means clean. But because people were effectively throwing all of their garbage outside the walls, the castle would have been fairly hygienic.