Illustrative of nonionic surfactants are alkylpolyglycol ethers such as ethoxylation products of lauryl, oleyl, or stearyl alcohols or mixtures of alcohols, such as coconut fatty alcohols; alkylphenol polyglycol ethers such as ethoxylation products of octyl- or nonylphenol, diisopropylphenol, triisopropyl phenol, or di- or tritertiarybutyl phenol.