Green buildup near gas port

[Ian]

I just completed a thorough cleaning of my Vepr and noticed a small green buildup near the entrance of the gas port in the gas block. I was able to clean most of the inside of the gas block using Hoppe’s #9, but I couldn’t reach this spot. I’m guessing it’s copper, but I'm not sure of the best way to reach it and remove it. Any suggestions would be welcomed.

For the record, I used Mpro7 for the bore only, and CLP everywhere else. I didn’t take off any more finish :)

Thanks,
Ian

[HPK]

I keep a stock of pipe cleaners from the local tobacco store on hand. They're not only good for reaming gas ports but can be bent into odd shapes for use around the trigger group and to get into all the other nooks and crannies in the receiver.