The present invention relates to the removal of subsurface contaminants and methods of using same. In more particular, but not by way of limitation, the present invention relates to an integrated method for remediating subsurface contaminants through the use of a low concentration surfactant solution (and methods of making and using novel surfactant solutions) followed by an abiotic polishing process to thereafter achieve a substantially reduced subsurface contaminant concentration that surfactant flushing alone cannot achieve. The present invention is focused on remediation of high viscosity hydrocarbons, such as heating oils or coal tars, with a combination of pre-injection of bio-co-solvent and surfactant (and polymer) flush approach.