Regina's instructions in their original can lids say to clean with kerosene or gasoline (!) soaked into the assembly by immersion, then to spin the freewheel using compressed air at the junction of the rotating hub/ non-rotating body. Once completely dry, lube with a lightweight machine oil. I use WD 40 sprayed directly onto the junction area as I turn it with the thumb of the hand holding the freewheel, and then spin it for a few munties once it is sucked into the gap (you can hear the difference as the solvent soaks the bearings and pawls inside). I let it dry at least 24 hours, and then use a lightweight chainlube (wet) to lubricate in the smae manner. I've not had to completely disassemble one, and have no intention of doing so.

Cleaning the outside of the gunk between the cogs makes it look pretty, but is a purely cosmetic move. The lube is needed on the inside, where you can't see.