Just saw this on Castor Oil: Not Just for Sick Stomachs Anymore - Associated Content - associatedcontent.com
For sure, no one should try to make castor oil by hand. The seeds of the castor bean are among the most deadly seeds on earth. As well as containing castor oil, the seeds of the castor bean plant also contain ricin -- a poison which is extremely toxic and most often fatal to insects, animals, and humans. In fact, nearly every type of animal is susceptible to ricin poisoning. Sap-sucking insects will die within 24 hours of eating castor bean foliage and the plant is fatally toxic to pets and livestock such as dogs, rabbits, horses, chickens, ducks, cattle, goats, sheep, and swine as well.
So I would rather stick to the Walmart/Target/local pharmacy brand than to try to make it.
Wow. I'll leave it up to the pro's.