Gunsmithing Any trick on AR barrel refinishing??

[Lead Heads]

I scratched my Rock Creek barrel on my AR taking off and reinstalling the gas block. Barrel is the matte grey color. Anybody have any tricks to make it look good again?
Thanks

 

[tacguns]

oxpho-blue creme and some 0000 steelwool

 

[CASDB]

Touch up pen and move on.