Skor:
Not in the UK. I can't imagine the germs that must collect in those things. I assumed they don't get cleaned between every crew.
At my employer (U.S.) we had a supply of wet alcohol wipes on the flight deck that had been approved by the company medical department. We carefully cleaned the mask when we originated or replaced another crew, and then tested it both for O2 flow and the mic.
Made sense to me.
I jump seated on a couple other major U.S. carriers who did not do such a test.