Single phase microemulsions (SPMEs) and in situ-formed microemulsions may be used to clean up and remove non-polar materials from reservoir production zones of oil and gas wells. This clean up occurs by solubilization of the non-polar material into the microemulsion when the treatment fluid contacts the non-polar material. An in situ microemulsion may be formed when one or more surfactant and a polar phase (e.g. water or brine), and eventually some small amount of organic phase, contacts the reservoir formation and solubilizes the non-polar material encountered in the porous media. The microemulsions are effective for removing the formation damage caused by non-polar materials which include, but are not necessarily limited to oil-based mud, synthetic-based mud, paraffins, asphaltenes, emulsions, slugs, and combinations thereof.