Best material I've found for slicking is Cordura, a nylon fabric made by DuPont.
I usually bevel my edges, then sand them with 400 grit on a damp edge, then 600 grit on a damp edge. Next I dye them. I dye before I slick, because the process of slicking compresses the fibers together and if done correctly will not dye very well, and I don't like the "fake" look of edge kote, I prefer spirit dye. NextI slick with a hardwood slicker on a damp edge, then damp again and finish with the cordura.
Jeff Mosby has a method that I'm going to try soon that adds another few steps of sanding in there somewhere. But this has worked for me.
Marlon