Yup - doms and dommes need to clean their implements after use. They could of course have the sub clean them, but my personal take on it is that there is a matter of personal responsibility involved here, especially if they're being used on more than one person.
Oh, just wait til I get to the "cleanliness is next to hawtliness" article, then! (it's either issue 3 or 4, I forget which) I guarantee when you read the reason I felt compelled to write it you jaw will be on the floor, good sir. The floor!