Abstract: A chemical composition and methods for use in the recovery of viscous oil and other desired hydrocarbons from subterranean reservoirs and from excavated material comprising oil sands or oil shale, and to remediate contaminated soil and subterranean reservoirs. Adding the composition to viscous oil renders it pipelineable by significantly reducing its viscosity. The chemical composition comprises an alkane, an ether, and an aromatic hydrocarbon. The composition is an organic solvent mixture that interacts highly favorably with non-polar hydrocarbons but is mostly immiscible with water and acts as a diluent, lowering the viscosity and raising the specific gravity of viscous oil. Additional water and heat are not required. Methods of using the composition in subterranean reservoirs and with excavated material including oil sands or oil shale and contaminated soil and subterranean reservoirs needing remediation, are highly efficient, economical, and reduce or eliminate adverse environmental consequences.