And keep in mind the amount of turpentine that would end up in the fabric is really very small. It's not remotely the same thing as what MzMolly's mom did!
You could also probably substitute something like sweet orange essential oil, which is also very good at loosening up heavy grease, adhesive residue, and similar gunk, or mineral spirits (not mineral oil).
Lest one assume sweet orange EO is safer than turpentine, think again -- the flash point is roughly 115-130 deg F for sweet orange EO vs roughly 95 deg F for turpentine. Not a great difference as things like that go.
edit: Here are other threads in which Mike talks about using solvents in soap:
I have made petroleum soaps....ones with mineral oils, petroleum distillates, and hydrocarbons like kerosene. These products don't saponify but you can add between 10-20% of the total weight of your oils without harm. I mix them in at trace. I would imagine the petroleum jelly would make a very moisturizing bar. Source:
http://www.soapmakingforum.com/showthread.php?t=7114
The kerosene smell dissipates quickly once you rinse your hands or the article of clothing in the case of the stain stick. No additional fuss is needed with the kerosene. Just pour it in to your melted oils. It's flammable, but not explosive like gasoline or turpentine, which I heartily do NOT recommend using. Just keep it out of the reach of children like you would with other chemicals. It's the same stuff they used to fill lamps with. For stain sticks, just make up a 100% lard or palm batch. Use soapcalc/soapmaker etc.... to determine lye for 0% superfat. Add 1.6 oz kerosene for each pound of melted oil, add your lye, and stick blend to a thick trace.....you want a heavy trace to minimize the chance of curdling. Then I pour it into a mold, I don't bother insulating. When it's set up, I cut the soap into butter sized sticks. These will remove soaping oils, and they're dirt cheap to make.... You can always label them with "petroleum distillates" and be perfectly correct. If you want something odor free that will sub for the kerosene.....go over to the art supply section and look for odorless turpentine substitue....."petroleum distillates" is still the correct label. Turpenoid is what I buy, and it doesn't compete with fragrance oils. Basically, these stain sticks are nothing more than a homemade version of Fels Naptha.....it uses the same products to cut oils. Source:
http://www.soapmakingforum.com/showthread.php?t=10966&page=3
and yet another edit: Here's a similar recipe by another SMF poster:
"...a recipe from my great grandmother that dates back to the 1920's...."
1 can of lye
½ cup of kerosene
½ cup borax
½ cup sugar
5 pints washed, melted grease
2 pints water
Source:
http://www.soapmakingforum.com/showthread.php?t=15719
And one more edit: The flash point of kerosene is roughly 100-150 deg F.
