How clean is the inside of brass supposed to be after tumbling?

[SPU]

Deadshot has me convinced to get a stainless pin setup when my $70 ultrasonic cleaner eventually dies. In the meantime, 24-32 minutes in the ultrasonic and pockets, outside and 80-90% of the insides are colored brass yellow. Not for everyone, and not as clean as SS pins, but cleaner in a shorter time than other methods I've seen.