A long soak (3 hours or more) in bio detergent initially at 30 deg C does the job nicely. As a small country parish church, we tend to be pragmatic about this sort of thing.

Mind you, IIRC the Book of Common Prayer does say that leftover consecrated elements should be "consumed reverently" by the celebrant assisted, if necessary, by communicant church members. We understand "reverently" to exclude saying "cheers" on draining the Cup. "The Lord Jesus, his very good health" might be marginally acceptable.