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Around here we call it Stoddard or Stanisol. http://www.cenex.com/~/media/cenex/files/lubricants/stoddard%20solvent/stoddard%20solvent_pds-g23-02.ashx
Hope this helps.

You might try soaking it a few days in clean Stoddard Solvent. That's what I do with the stones in my machine shop when they get clogged with swarf, cutting oil, and grease from my hands. :)