Methyl-tert-butylether (MTBE), ethyl-tert-butylether (ETBE) and tert-amylmethylether (TAME) are generally accepted on the market as antiknock agents (additives) and even as a feedstock of the chemical industry, but are associated with environmental dangers, including contamination of ground water. The authors present a method to remove low concentrations of these ethers with ultrasound.