super sculpy

My experience has been once Super-Sculpy is baked and cured it's pretty much impervious to most chemicals. You might have a problem with some organic solvents (MEK, benzene or methylene chloride) only because S/S is a polymer. Turpentine in small amounts should be fairly safe. Alcohol shouldn't be a problem. However, if you're really being cautious you might forego chemistry altogether and try 400-600 grit sandpaper or #0000 steel wool. The steel wool might also add a little polish to the surface and remove some small defects. It might be a more tedious process but safer.

I know from experience that regular Sculpy is somewhat vulnerable to water, but I think Super Sculpy is okay. Never used it, but I know that it is more like plastic when cured, whereas the regular stuff is kind of like hardened bread dough. I know of one sculptor, who works for VLS, who uses SS for his faces. He thins spot putty down with liquid model cement and then uses that as a light primer to fill in small gaps and whatnot and to show any other flaws. That tells me that when cured, SS should be fairly resistant to liquid cement, and therefore would also be resistant to thinners and the like.

 If you really have doubts, mix up and bake off a lump, paint it and then see what the thinners do to it.