You have a great deal of good information here and I'm going to check it out. Thanks.
I am writing to tell you what I do, not to suggest what you should do/try...
I get terrible headaches if I am in a room with turpentine - even the "odorless" kind, and I've gone through a lot of substitutes and found the following....
"Turpenoid Natural" really messes up my brushes if I don't get every speck of it out when I'm done painting. If it gets mixed up in my paint, it prevents the paint from drying. I don't much like this product.
I do use a citrus-based thinner called Bio-Shield. It does not smell like citrus (thank heavens!) and it does clean my brushes. If it gets mixed up in my paint, it doesn't hurt anything. But basically I use it as a brush cleaner - seldom as part of a medium. The few times that I have mixed it with damar varnish and linseed oil to use as a medium, it has worked well....
I use "Silicoil" as a final brush wash. It is probably lethal stuff, but it does not give me a headache and it cleans my brushes easily and well. (I don't like to use soap and water as I feel it hurts my brushes). I leave the lid on the Silicoil until I am done painting and it is time to clean up. This product should never be mixed with paints.
I do use Liquin as a medium. It is also pretty lethal stuff, except that for some reason it doesn't bother me.
I have a well ventilated studio and can tolerate a lot of chemicals, but never turpentine (or hardware-store paint thinner) in ANY form!
