Carbon buildup

[Dennis]

I just finished tumbling my 6.5x47 Lapua cases. After inspecting, I took a flashlight and looked down the case. I could visibly see carbon buildup from the flash hole to the outer edges of the case! The rest of the inside case looked clean. I check several and all were the same!

Is this normal, or how do you remove it?

[drybean]

yep do not worry about it
drybean

[okie2]

PUT THEM IN HOT WATER WITH DAWN DISH SOAP

[frank1947]

ultrasonic cleaner will make the inside look new