Flux removing composition

An aqueous cleaning concentrate capable of removing flux residues from circuit assemblies having a pH of greater than 10 to about 12 and comprising from about 70 to about 90 wt. % water and from about 5 to about 30 wt. % of a cleaning composition containing at least one alkali metal salt present in amounts sufficient to provide said concentrate with said pH of from greater than 10 to about 12, an alkali metal silicate corrosion inhibitor in addition to said one alkali metal salt and a surfactant formulation comprising a mixture of an alkoxylated nonionic surfactant and an N-alkylpyrrolidone, wherein said alkyl group contains 6 to 20 carbon atoms, said alkali metal silicate being characterized by the formula M.sub.2 O:SiO.sub.2 wherein M represents an alkali metal and in which the ratio of M.sub.2 O to SiO.sub.2 is between 1:1.6 and 1:4.0, wherein said N-alkylpyrrolidone comprises 1 to 1.5 wt. % of said concentrate, said concentrate being devoid of an anionic polymer for stabilizing said alkali metal silicate in aqueous solution.

A silicate-stable aqueous cleaning concentrate capable of removing flux residues from circuit assemblies and having a pH of from greater than 10 to about 12, comprising from about 70 to about 95 wt. % water and from about 5 to about 30 wt. % of a cleaning composition containing at least one alkali metal salt present in amounts sufficient to provide said concentrate with a pH of from greater than 10 to about 12, an alkali metal silicate characterized by the formula M.sub.2 O:SiO.sub.2 wherein M represents an alkali metal and in which the ratio of M.sub.2 O to SiO.sub.2 is between 1:1.6 and 1:4.0, and a surfactant formulation including an N-alkylpyrrolidone, wherein said alkyl group contains 6 to 20 carbon atoms, said concentrate comprising from 0.6 to 3 wt. % of said N-alkylpyrrolidone, said concentrate being devoid of an anionic polymer for stabilizing said alkali metal silicate in aqueous solution.