Removal:
1) Take a piece of masking tape.
2) Puncture it
3) Place it with the hole over the pin (to protect the scales from damage)
4) Start filing the pin until it's flat.
5a) Drill it out (it's 1/16")
or
5b) Keep on filing until you're almost down to the scale
6) Gently pry the scale off and push out the pin.

Attachment:
You'll need a 1/2" (approx) long 1/16" piece of a brass rod (any better equipped hobby shop) as a pin, 2 #0W brass washers to go between the tang and the scales, 2 #0 brass washers to go outside the scales (microfasteners.com). Trim the pin to the right length and gently tap on a hard surface (a small 11lb anvil costs like $10) with a small balpeen hammer to peen over and tighten. By gently I mean gentle enough to hit a finger and not feel any pain.

There are better descriptions than mine, just search the restoration forum. However, make sure to get the #0W washers.