A proprietary solvent made pursuant to this formula shall be made with alcohol denatured in accordance with S.D.A. Formula No. 1, 3-A, or 3-C and shall contain, for every 100 parts (by volume) of S.D.A.:

(a) No less than 1 part (by volume) of one or any combination of the following: Gasoline, unleaded gasoline, heptane, or rubber hydrocarbon solvent, and

(b) No less than 3 parts (by volume) of one or any combination of the following: Ethyl acetate (equivalent to 85 percent ester content, as defined in §21.107 of this chapter), methyl isobutyl ketone, methyl n-butyl ketone, tert-butyl alcohol, sec-butyl alcohol, nitropropane (mixed isomers), ethylene glycol monoethyl ether, or toluene.

[TD TTB-140, 81 FR 59457, Aug. 30, 2016]