A mixed cleaning solvent containing dichlorotrifluoroethane and dimethoxymethane without containing Flon #113, which is suitable for cleaning and degreasing printed circuit boards and for eliminating flux residues and dust particles adhering thereon and which reveals high cleaning ability without occurrence of whity specks of volatilization residues including ionic residues on the treated surface with possible attainment of high stability to decomposition of the solvent component.