This is head cleaned up with Brake Cleaner, WD 40 and 600 grit silicon carbide sand paper.
I also used a feeler gauge and straight edge to check for flatness spec of .05mm
Not sure how to accurately check surface roughness value Ra of 30 which the Fel Pro MLS requires.
You need some fancy lab equipment which is not practical.
You cant really tell by feeling or touch.
Im just going to assume that 600 grit sandpaper done lightly will give me at least 30 Ra,
as its supposed to be good for 2-3 Ra on molds. See pic below for the Ra values vs Sandpaper grits