We recently had blow-in insulation installed in our walls from the exterior. They drilled 2-inch holes and after blowing in the insulation, plugged them with wooden plugs and plastered them over. I understood that it's my responsibility to sand the plugs and repaint them. My question is the best way to do this. How much sanding is needed, and what type of sandpaper should I use? Some of the siding planks looked like they were cracked in the process, should those be replaced, or are they ok? The house is double-sided, so there's another layer of siding underneath. Also, the plaster in one of the plugs is still soft to the touch after almost a week, should that be a concern?