Dear Michele & Karin (and our fellow artists),
According to the manufacturer (whose salesman and chemist I've contacted directly), the only thing left behind after SafeKlean evaporates is a little linseed oil, which will of course oxidize and harden as part of the layer of paint.
So unless they are not telling the truth, there should be nothing to "turn a painting green" over time (a prime concern of mine, too, of course).
I tend to trust the manufacturer, given that their Best-Test rubber cement has been a reliable standby for a great many years.
SafeKlean is also certified to be non-toxic and non-flammable. According to the BioShield website, that product is based on citrus peel; and according to that Gamblin Solvent Chart I referenced (
http://www.gamblincolors.com/materials/solchart.html), solvents based on citrus peel have as their active ingredient d-Limonene (4-Isopropenyl-1-methylcyclohexene, according to my trusty old Handbook of Chemistry and Physics); they do dissolve apparently all artists' resins (like only turpentine and SafeKlean); they are used in making mediums (in addition to being used to dilute paint and to clean brushes); they have a flashpoint of 116