The composition of claim 1 wherein said alkali or alkaline earth metal salt of mercaptan or mercapto acid has a formula selected from the group consisting of ##STR65## and ##STR66## where M is an alkali or alkaline earth metal;M1 is an alkaline earth metal; n is 1 when M is an alkali metal; n is 2 when M is alkaline earth metal; R is a hydrocarbon radical having from 1 to 22 carbon atoms and is se