Bluish green stuff on my muzzle break

[globeguy]

After I cleaned my barrel with Slip 725 degreaser, I see bluish green coat on my muzzle break. Anyone have any idea what this is? My guess is some of the carbon inside the barrel got pushed out on to my muzzle break then chemically reacted with the degreaser.

This was my first time using 725 on an AR15, haven't seen this happen on my handgun when using 725 degreaser.

[steelonsteel]

sounds like copper fouling.

[fixit69]

That's when you know your on the right track. Clean and move on.

[Scorpion]

Same thing happened to me. That's just copper fouling; Hoppes #9 got it right out for me.

[globeguy]

Same thing happened to me. That's just copper fouling; Hoppes #9 got it right out for me.
Is it a big deal to just leave it on there? The color itself doesn't bother me, so if it won't damage the metal I rather not bother cleaning it up.

[Scorpion]

I wouldn't leave it on there, but I can't see it doing much harm. It's simple to clean though - it just wipes off with bore cleaner.

[PRGGodfather]

Definitely copper fouling. It's what causes copper on buildings to look green over time. It's not a problem, and bore cleaner will help.