[Heathkit] EV-638 (HDP-21A) restoration

[Chris Codella, W2PA]

Have any of you tried to restore the Heathkit HDP-21A (a.k.a. 
Electrovoice 638) microphone? 

The base has a tendency to get pitted and eventually lose its original 
finish over much of its surface. The base is much more prone to this 
deterioration than the rest of the microphone.  I almost never see one 
for sale that doesn't have this problem.  So I'm wondering if any of you 
Heathkit fans have any ideas on how to restore it.   (Yes - I've seen 
the painted ones - that doesn't count as restoration.)

73,
Chris, W2PA