Hey Jerry, I just went with what I found online, which is dish soap and warm water.
Both stems were cleaned that way, and should be ready to smoke.
I drenched pipe cleaners in dish soap and spent 30 minutes or so running them back and forth through the stem, and rinsing in between with warm water.
Be sure to keep the stems cleaned out good after a smoke, it was tough to get just a little bit of old tar out of them.