Black and green polishing compounds
Round diamond burr rotary tool bit
I never tried this before so wish me luck. It either works or I spent a lot of time cutting out a knife and will ruin it. First I gathered up some poster board, a pencil, a utility knife, painters tape and a set of compasses.
First. I outlined the knife blade on a piece of poster board. Then using a utility knife partially cut the outline of the knife.