I've gotten very good results with heptane, and a warm water bath vac purge (3x repeated). You could even dissolve the oil in a foodsafe alcohol (pure ethanol, acetone, isopropyl) so long as they are completely dry and pure, then evep and vac purge again.
Naptha has alot of different hydrocarbons in it, and heptane is a much refined version of naptha that evaps faster, and cleaner imho. As usual, always check your msds/do an evap test.
Just purge the hell out of it, and do an alcohol redissolve and another purge. Should get all but minute traces of the heptane out, and very low concentrations of alcohols that are not toxic in the doses that would be present as impurites that did not boil off.
Works just as well as butane without the danger of butane. I refuse to pressurize a vessel that is either metal and prone to electrostatic igniton, or a plastic that could shatter from temperature stress. Too many bad stories, and a few bad personal expirences in that dept.
You can also do a iso/etoh/acetone extraction first, and then do a hot water bath on that oil extracting with heptane. Will leave all the polar bad tasting crap behind and give you very good oil/wax if done correctly.
Supercritical gas extractions are sketchy enough, let alone supercritical highly flammable gases. CO2 mabey, but only with the right equipment (unfortunately is only viable on a larger commercial scale due to the mechanics of supercritical co2 extractions. Though it did produce the best wax i've ever tasted, co2 wax that is.
"let those who have talked to the elves, find each other and band together" -TMK
In a society in which nearly everybody is dominated by somebody else's mind or by a disembodied mind, it becomes increasingly difficult to learn the truth about the activities of governments and corporations, about the quality or value of products, or about the health of one's own place and economy.
In such a society, also, our private economies will depend less upon the private ownership of real, usable property, and more upon property that is institutional and abstract, beyond individual control, such as money, insurance policies, certificates of deposit, stocks, etc. And as our private economies become more abstract, the mutual, free helps and pleasures of family and community life will be supplanted by a kind of displaced citizenship and by commerce with impersonal and self-interested suppliers...
The great enemy of freedom is the alignment of political power with wealth. This alignment destroys the commonwealth - that is, the natural wealth of localities and the local economies of household, neighborhood, and community - and so destroys democracy, of which the commonwealth is the foundation and practical means.โ - Wendell Berry