I no longer use jags, have switched to nylon brushes wrapped with a cotton patch. I've tried nearly all the solvents, potions and lotions available. There are several that do very well on copper but I have abandoned the ones containing ammonia. I have returned to Bore Tech Eliminator. Although there are a few solvents that work just about as well, I haven't seen anything that beats it.
I tried the 2 new solvents from Bore Tech, Cu+2 Copper Remover and C4 Carbon Remover. They work very well but in my opinion, no better than Eliminator. To keep things simple (like O'reilly, I'm a simple guy), I'd rather use one solvent than two, so Eliminator is it for me. That's not to say I won't try the next new wonder salve that hits the market.
I wasn't among the fortunate few that got to sample Coppermelt. If that ever becomes available again I will absolutely try it.
Festus