Well upon streaking both Diggers and Sceneys shellite onto a mirror tonight, here is what I found:

- Diggers seemed to leave no trace of any oily remains

- Sceneys left a very obvious oily film

Diggers also smelt much more akin to Zippo brand naphtha, it had that "sweet" smell to it.  The Sceneys smelt a lot different, had a harsher smell, more like paint thinners, it definitely has something extra in there.

I also wasn't sure if the fact that it left an oily film naturally means that I shouldn't use it for extractions, or if it will be okay still?  I simply don't know how the Sceneys shellite will perform at low temperatures and whether this oily residue will actually contaminate the spice when doing a freeze precipitation - I imagine because it doesn't evaporate off at room temperature that it probably will sit in the precipitated spice even with a fan blowing on it and stay there, thus contaminating it though.