a thioacid selected from the group of acids having the formula R1???SH, where R1 comprises at least one C2-C12 carboxylic acid moiety; an amine halide salt having the formula: where X is a halide anion and R2 is an aryl or aliphatic C1-C12 alkyl moiety; and a diphosphonic acid having the formula where R3 is a C1-C12 alkyl moiety.