I agree with avoiding power tools. I usually hand-file them off. Mask around the washer with tape--I usually use electrical tape. Make a hole in the tape just big enough for the top of the pin.

I then grab a flat mill file and hold it vertically, with one end resting on my knee. I'm sitting down for this. Then carefully file the razor up and down on the stationary file.

Keeping the file still and moving the razor gives me a lot more control. The danger is letting the scales roll up or down, in which case the tape should save your butt.

I sometimes repin restorations two or three times if necessary to get the blade centering properly, and this way I can remove a pin without messing up a nice CA finish. Should work just as well on your minty scales.

Josh