Okay, I promised a pic and here it is. This is how my stoned extractor looks . . .
The only surfaces touched were the top and bottom. And I did it as Dave described, on a flat hard Arkansas stoned lubed with honing oil.
The gritty and binding extractor movement is what I had originally. It was also very
difficult to get out of the slot during disassembly. Now it moves freely and will drop out under its own weight.