Have you checked into the possibility of growing them commercially? The "weed" then becomes a "cash crop"...............
http://en.wikipedia.org/wiki/Castor_oil
From WIKI:
Compared to other seed oils which lack the hydroxyl group, castor oil demands a higher price. As an example, in July 2007 Indian castor oil sold for about US$0.90 per kilogram (US$0.41 per pound)[3] while US soybean, sunflower and canola oil sold for about US$0.30 per kilogram (US$0.14 per pound)[4]
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Uses
Castor oil in food
In the food industry, castor oil (food grade) is used in food additives [5], flavorings, candy (i.e., chocolate) [13], as a mold inhibitor, and in packaging. Polyoxyethylated castor oil (eg. Cremophor EL)[14] is also used in the foodstuff industries.[15]
Medicinal use of castor oil
The United States Food and Drug Administration (FDA) has categorized castor oil as “generally recognized as safe and effective” (GRASE) for over-the-counter use as a laxative.[16] However, it is not a preferred treatment for constipation.[17] Castor oil can also be used to induce childbirth, but doing so is sometimes cautioned against because it can lead to complications for the childbirth process, including dehydration of the mother and other risks associated with any inducement of pregnancy, such as fetal distress from too strong contractions, increased risk of uterine rupture, unintentional prematurity of the baby, and increased pain for the mother.[18]
Undecylenic acid, a castor oil derivative, is also FDA-approved for over-the-counter use on skin disorders or skin problems.[19]
Ricinoleic acid is the main component of castor oil and it exerts anti-inflammatory effects.[20]
One study has found that castor oil decreased pain more than ultrasound gel or Vaseline during extracorporeal shock wave application.[21] Therapeutically, modern drugs are rarely given in a pure chemical state, so most active ingredients are combined with excipients or additives. Castor oil, or a castor oil derivative such as Cremophor EL (polyethoxylated castor oil, a nonionic surfactant), is added to many modern drugs, including:
* Miconazole, an anti-fungal agent;[22][23]
* Paclitaxel, a mitotic inhibitor used in cancer chemotherapy;[24]
* Sandimmune (cyclosporine injection, USP), an immunosuppressant drug widely used in connection with organ transplant to reduce the activity of the patient’s immune system;[25]
* Nelfinavir mesylate, an HIV protease inhibitor;[26]
* Saperconazole, a triazole antifungal agent (contains Emulphor EL -719P, a castor oil derivative);[27]
* Prograf, an immunosuppressive drug (contains HCO-60, polyoxyl 60 hydrogenated Castor oil);[citation needed]
* Xenaderm ointment, a topical treatment for skin ulcers is a combination of Balsam Peru, Castor oil, and trypsin;[28][29]
* Aci-Jel, a gel used to create or maintain the acidity of the vagina (comprises acetic acid/oxyquinoline/ricinoleic acid - vaginal)[30]
Industrial castor oil
Castor oil has numerous applications in transportation, cosmetics and pharmaceutical, and manufacturing industries, for example: adhesives[32], brake fluids [33], caulks, dyes[32], electrical liquid dielectrics, humectants,[32] hydraulic fluids, inks[32], lacquers, leather treatments,[32] lubricating greases, machining oils, paints[32], pigments, polyurethane adhesives [34] , refrigeration lubricants, rubbers[32], sealants, textiles[32], washing powders, and waxes.
Vegetable oils, due to their good lubricity and biodegradability are attractive alternatives to petroleum-derived lubricants, but oxidative stability and low temperature performance limit their widespread use.[35] Castor oil has better low temperature viscosity properties and high temperature lubrication than most vegetable oils, making it useful as a lubricant in jet, diesel, and race-car engines.[36] However, castor oil tends to form gums in a short time, and its use is therefore restricted to engines that are regularly rebuilt, such as motorcycle race engines. Biodegradability results in decreased persistence in the environment (relative to petroleum-based lubricants[37]) in case of an accidental release. The lubricants company Castrol took its name from castor oil.
Since it is has a relatively high dielectric constant (4.7), highly refined and dried castor oil is sometimes used as a dielectric fluid within high performance high voltage capacitors.
Castor oil is the raw material for the production of a number of chemicals, notably sebacic acid, undecylenic acid, nylon-11. A review listing numerous chemicals derived from castor oil is available.[38]
Castor oil is the preferred lubricant for bicycle pumps, most likely because it doesn’t dissolve natural-rubber seals.[39]
The noted price differential of $0.41 per pound versus $0.14 per pound for other “common” oil seed crops is huge. If they grow as “weeds” on your place you may be sitting on a “gold mine”...................