There are two things here: sterilizing and polishing.

As mentioned, bleach is not recommended because of the aluminum tenon, though I did a couple of aluminum tenon pipes with a 50/50 bleach/water solution and others with Oxyclean and they are none the worse for wear. My polishing went through a progression from 600 right up to 12k micromesh. Then I used some stem polish to protect them. Probably overkill, but it was fun.

Here are my restored stems from a few different pipes, all with aluminum tenons:
Before:


After:


Full thread: http://straightrazorpalace.com/finer...sportsman.html

A couple more:
Before