What do y'all use for touch up on Steel and aluminum?  I installed my first Noveske barrel and will I appreciate the tight tolerances it did require more effort than my other builds.  The extra effort earned some extra character.  I can deal with the scuffs from an aesthetics stand point.  Especially considering the gas block is covered up by the HG but I live in a coastal region so I know what happens to bare steel.  What do you use?  Spray paint sufficient for anti corrosion?  How does the off the shelf stuff hold up to barrel heat?

While we are in the topic might as well throw aluminum touch up suggestions in as well.  

Thanks

On aluminum, I use Aluminum Black and on steel, I use either Duracoat or cold blue.

Birchwood Casey Touch up pen

Sharpie

Depending on what part its on we use Dicropan t4 at the shop or a touch up pen.

+1 to this.  Birchwood Casey makes the Aluminum black chemical I use.  Any one of the many cold blue preparations is suitable.  Don't expect perfect results, esp on the Aluminum. Every aluminum or steel alloy comes out slightly different and the surfaces must be completely degreased for the stuff to work. - CW