Originally Posted by
shovelhd
When the chain starts leaving gunk on the derailleur jockey wheels, it's time to completely clean the drivetrain. I have a parts washer with mineral spirits. The chain and cassette are removed and cleaned while the crank and derailleurs are cleaned on the bike. How often depends on conditions. It could be every 3-4 weeks or it could be twice in one week.
that's serious.
I use one of those chain cleaner thingy's every few weeks, it takes off the gunk, then I use a brush and rags to clean the jockey wheels and chainrings. I only take off a chain to replace it.