The present invention relates to corrosion inhibitor systems, in particular to cleaning and corrosion inhibiting compositions for surfaces of aluminum or colored metals and alloys thereof under alkaline conditions, especially in the food and pharmaceutical industries. The cleaning and corrosion inhibiting compositions comprise as a corrosion inhibitor at least one alkyleneoxy alkylphosphate di- or triester having the general formula (I) where Z is either --O--M or --O--(AO)n.sup.2-- Alkyl wherein M is an ammonium, alkali metal or alkaline earth metal cation, Alkyl is a C.sub.5-C.sub.22 alkyl or alkylaryl group, AO is a C.sub.2-4-alkylene oxide unit and n.sup.1, n.sup.2 and n.sup.3 each are integers from 2 to 10.