Dispersion of oil-tank sludge using compositions of cationic, anionic, and nonionic surfactants followed by isolation of synthetic oil is a processing method with several disadvantages such as residual S-containing compounds and toxic spent solutions. The present work proposes the use of polycomplexants (sodium salts of iminodiacetate derivatives of fatty-acid triglycerides and mucosaccharides) as promising and affordable replacements for traditional surfactants. A methodology for processing oil-tank sludge using these compounds and results of laboratory tests showing decreased S contents and significantly lower densities and viscosities of the oil-tank sludge are given.