Process for cleaning soiled metal surfaces and substances useful for such process

An alkoxylated polyethylenimine (B) with a polydispersity Q=Mw/Mn in the range from 3.5 to 10 and an average molecular weight Mw in the range from 2,500 to 1,500,000 g/mol, wherein the alkoxylated polyethylenimine (B) has a polyethylenimine backbone and alkylene oxide units, wherein the polyethylenimine backbone and the alkylene oxide units are in a weight ratio in the range of from 1:2 to 1:50, wherein a molecular weight distribution of said alkoxylated polyethylenimine (B) is multimodal but not bimodal.