Restoration of Pipes

Have you considered cleaning off the stem yourself?  There's a lot of information on various sites about cleaning and restoration.  Unless the stem has some severe issues, restoring it to a nice glossy black is a pretty straightforward procedure.

There are way to deal with that.  An image would help. 

Here's what I do.  First of all, any oxidation has to be physically removed.

I use a micromesh kit, which consists of a number of sanding pads that range from coarse, which I use to sand off the layer of oxidized material, to very fine, which I used to polish the stem. You work your way through the range of pads, gently sanding in different directions to avoid creating patterns in the surface.  The final four grades I wet sand under running water.  It's a gradual process, but the result is a glass like black surface.  There are videos on youtube that show how this is done. 

If this seems like more than you want to take on, there are people who do restoration.  I don't know who does this on this forum, but I do know some very talented individuals who do exceptional work.  So if no one comes forward, let me know and I'll give you some names.