(a) from 0.1% to 10% by weight of a surfactant selected from the group consisting of (1) quaternary ammonium compounds, wherein at least one of the hydrocarbon groups linked to nitrogen is a linear or branched alkyl group containing at least 12 carbon atoms and preferably 16-20 carbon atoms, and being saturated or unsaturated, and wherein two or three of the groups linked to the nitrogen are indep