You make it sound so easy. It wouldn't have been immodest to title this thread "Night & Day".Actually, i soak the stem in regular bleach! first, i wash it to remove any oils then soak for about 5 minutes. Then i wash it again,with a light scrub with a fiber pot scrubber followed by another 5 minutes in the bleach.
Rinse, dry, and finally buff it out on the linen wheel.