This is a re-post to.
I copied the Diosol formula posted in one of the yahoo groups several years ago by a chemist who lab analyzed and posted the formula. This is as posted verbatim.
"38% by vol toluene, 41% by vol xylene and 21% by vol Solvesso 100 (a long evaporation rate aromatic hydrocarbon solvent). Getting the toluene and xylene is not difficult, but the Solvesso 100 is only available through chemical suppliers."
I was fortunate to have a local paint manufacturer that could provide the Solvesso 100. Solvesso is also known as Naptha and available in various grades.
All the ingredients were available at Sherwin Williams 6 months ago.