BC BR Ride Height

I’m trying to set the ride height on my BC BR coils. I can’t seem to figure out how to take the coil apart to get the dang bump stop off the rears. I would imagine that I’m supposed to use the Allen screw top and get the damper unthreaded right below that adjuster, but obviously the shaft is spinning in the damper. So how do I hold the shaft tight enough without marring it to unscrew the top?

picture attached.

Heat. Heat is always the answer 😂