I will post a pic later to show but this handwheel had about 10% of the nickel plating left.
I work with coal and gas forges regularly, so not so stressed by sparks
Although I have to say in doing this process I don't get any sparks at all, I use a 6 inch diameter soft/fine wheel on a 1/2 HP motor.
You're also quite correct if this had it's nickel plating the wire Wheeling would just remove it in a heartbeat. In fact that's why I chose the wire wheel for this is because it would remove what's left of the nickel plating to even up the surface.