A mixture suitable for use as a foam-suppressing surfactant additament in cleaning compositions for mechanized cleaning processes comprises at least two mixtures of alkoxylated alcohols IR--O--(C.sub.2 H.sub.4 O).sub.x --(C.sub.3 H.sub.6 O).sub.y --H (I)where x is an average degree of ethoxylation between 1 and 12, y is an average degree of propoxylation between 1 and 15, one alkoxylated alcohol mixture carries straight-chain or branched C.sub.8 -C.sub.18 -alkyl groups as the radical R and one other alkoxylated alcohol mixture carries straight-chain or branched C.sub.10 -C.sub.20 -alkyl groups as the radical R, subject to the proviso that the two radicals R differ by at least 0.5 in the average number of carbon atoms, and the two alkoxylated alcohol mixtures present in a ratio of from 10:90 to 90:10.