Whatever abrasive you use, be sure to go only in one direction. If you go back and forth or switch the blade end-to-end, you will make something of a mess. I assume you're picky about the finish or you wouldnt be asking.
A nice slow way to go about it, depending on the hardness of the blade, is the scotchbrite pad laid flat on a work bench. Strop. One direction.
Good luck.