With sanding of the inserts - Find a piece of timber the same size as a sanding block, wrap the sandpaper around the sides of the block and then place it in a vice. Then use a bit of water and slide the insert back and forth. Keep doing this through the grades, starting at 240 ish and moving up 400, 600, 800, 1000 then 2000. Then clean it with Novus 3 and then Novus 2.
