A quaternary ammonium compound of formula (X):

##STR00001## wherein R.sup.0, R.sup.1, R.sup.2 and R.sup.3 is each individually an optionally substituted alkyl, alkenyl or aryl group and R includes an optionally substituted hydrocarbyl moiety having at least 5 carbon atoms.

A quaternary ammonium compound of formula (X):

##STR00001## wherein R.sup.0, R.sup.1, R.sup.2 and R.sup.3 is each individually an optionally substituted alkyl, alkenyl or aryl group and R includes an optionally substituted hydrocarbyl moiety having at least 5 carbon atoms.

A composition including a quaternary onium hydroxide in a non-aqueous solvent, wherein the quaternary ammonium hydroxide has a concentration in the range from about 5% by weight to about 50% by weight of the composition; and imidazolidine-2,4-dione, wherein the imidazolidine-2,4-dione has a concentration in the range from about 10 to about 5000 parts per million of the composition.

A composition including a quaternary onium hydroxide in a non-aqueous solvent, wherein the quaternary ammonium hydroxide has a concentration in the range from about 5% by weight to about 50% by weight of the composition; and imidazolidine-2,4-dione, wherein the imidazolidine-2,4-dione has a concentration in the range from about 10 to about 5000 parts per million of the composition.