I've observed improvement over time. I have barrels that just don't foul, period. They only show carbon residue.
Even rough barrels usually improve post DBC. Some of those never quit fouling, just foul less and are easier to clean. Those usually will clean up with a few soaking treatments with Eliminator or similar.
I'm a DBC fan, treat everything, even new premium barrels. It can't hurt. Makes me feel better...
DF
