You might try a brief two-to-three-minute soak in chlorine bleach
This is the first time I've used bleach in the cleaning of a pipe stem . I used a 4 to 1 mix and the outcome was promising that is until I started sanding the stem with mesh. The beast once again emerged from it's slumber.
In the wee hours My wife made me stop working the smell had taken over the room in full force. So should I finish all my work on the stem back to it's shiny glory then soak in bleach as a finale step(I don't know if this will destroy the work i've done)
Or do I need to soak the stem longer then 4 minutes at a time.
My other question is what causes this stench? Hundreds of pipes have passed through my hands over the years in much worse shape then this one and the smell was never attached to one of them.