My evil trick to get them clean?
Get an old water pik. A few heavy towels to catch the spray/wrap it in and blast the joints squeaky clean. The idea that you have to replace perfectly good joints when they aren't stripped/worn always seemed to me like a cop-out. The water pik's diaphragm will eat itself from the solvent(though not initially) most likely, so this is the reason you use an old one.
edit - I suppose something like Simple Green might work as well, and not eat the diaphragm, but probably would be even slower than kerosene. (oh - new they run about $35 - tons cheaper than new axles)
