also, regarding
1, 2 ortho-Dichlorobenzene:
"Another type of use is in motor oil additive formulations.
It is also used as a solvent in paint formulations, as well as in compounds for removing paints, varnishes, lacquers, resins, gums, waxes, heavy greases, acetylcellulose, sulfur, organic sulfur compounds and oxides of non-ferrous metals.
In engine-cleaning compounds, orthodichlorobenzene is a specific solvent for the removal of carbon and lead deposits from carburetor and engine parts.
Orthodichlorobenzene is a superior solvent for rubber and tar, and is frequently used to dissolve tarry residues in stills and other processing equipment"
.