This is the history of drivetrains. Either you clean all routinely or you transfer from dirty to clean rapidly. Additionally what's a cleaning to one is not to the item being cleaned. As a shop wrench i have cleaned more drivetrains then most here at Bike Forums. I will say even with industrial solvent tanks (safetykleen most often) and air hoses there is almost always a bit of grime that is never removed. Or at least within the time frame allowed for paid work as well as my home/own bike stuff. I can't count the number of chains I've cleaned, air blasted dry and re cleaned only to have when I've whack them against a bike box still wet (from the second cleaning) to see more grime driven out.

So my choice is to clean often and keep the build up minimal.

BTW I cringe when i listen to the sales guys who say lubing then wiping it off is good maintenance. Seems to me that only gets the grime to float about the chain and then get pushed into it. Sure some comes off on the rag but more gets driven inside the links. Further any chain wipe off without the other surfaces of the drivetrain being cleaned is fooling one's self. Andy.