Abstract: A composition consisting of (A) an aromatic amine of the formula R--NH.sub.2 wherein R is a monosubstituted or disubstituted phenyl radical in which one substituent group is an alkoxy group of 1 to 4 carbon atoms in one of the positions ortho and para to the NH.sub.2 group and the other substituent is an alkyl group of 1 to 4 carbon atoms or a chlorine atom in any position on the benzene ring, the former substituent group is present when the radical is both monosubstituted and disubstituted while the latter substituent is present only when the radical is disubstituted, (B) from about 0.001 to about 0.20 percent by weight of a heterocyclic compound containing 2 to 8 carbon atoms, 2 to 3 sulfur atoms, 1 to 2 heterocyclic nitrogen atoms, at least 2 hydrogen atoms and a single heterocyclic ring with 2 or more carbon atoms, 1 to 2 nitrogen atoms and 1 to 2 sulfur atoms with the substituents on the nitrogen atoms being restricted to hydrogen atoms, and (C) from about 0.001 to about 0.