On all the Yugos I've built before (2.... :wink: ) I kept the original, worn, faded, pitted blue on the parts kits and left the nice DCI heat treat blue because it matched so well. However, on this, my third Yugo build, the DCI receiver actually had some rust and pitting from the heat treat process (I assume) so I HAD to bead blast it. To match the finish on THIS one I used cold blue on the receiver and new rivets to match the parts kit. I used a cotton ball, swabbed it, and then OOOO steel wool and oil rubbed it. I did that about 5 times to get the right color back and it worked OK. Normally I absolutely despise cold blue but it occasionally has it's uses.